Ink refill unit having a clip arrangement for engaging with the print engine during refilling

ABSTRACT

A printing fluid refill cartridge for a printing unit comprising an outlet arranged to be engageable with a refill port of the printing unit through which printing fluid contained in the refill cartridge is dispensable; a first engagement member arranged in the vicinity of the outlet and a second engagement member arranged in the vicinity of the refill port and configured to be removably securable with the first engagement member so as to engage and hold the refill port and the outlet together.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.11/014,749 filed Dec. 20, 2004, now issued U.S. Pat. No. 7,588,301,which is a Continuation-In-Part of U.S. application Ser. No. 10/760,254filed on Jan. 21, 2004, now issued U.S. Pat. No. 7,448,734, the entirecontents of which are herein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a high speed print engine for an inkjetprinter unit, and more particularly to a system for refilling the printengine with a selected quantity of refill ink.

BACKGROUND OF THE INVENTION

Traditionally, most commercially available inkjet printers have a printengine which forms part of the overall structure and design of theprinter. In this regard, the body of the printer unit is typicallyconstructed to accommodate the print head and associated media deliverymechanisms, and these features are integral with the printer unit.

This is especially the case with inkjet printers that employ a printheadthat traverses back and forth across the media as the media isprogressed through the printer unit in small iterations. In such casesthe reciprocating printhead is typically mounted to the body of theprinter unit such that it can traverse the width of the printer unitbetween a media input roller and a media output roller, with the mediainput and output rollers forming part of the structure of the printerunit. With such a printer unit it may be possible to remove theprinthead for replacement, however the other parts of the print engine,such as the media transport rollers, control circuitry and maintenancestations, are typically fixed within the printer unit and replacement ofthese parts is not possible without replacement of the entire printerunit.

As well as being rather fixed in their design construction, printerunits employing reciprocating type printheads are considerably slow,particularly when performing print jobs of full colour and/or photoquality. This is due to the fact that the printhead must continuallytraverse the stationary media to deposit the ink on the surface of themedia and it may take a number of swathes of the printhead to depositone line of the image.

Recently, it has been possible to provide a printhead that extends theentire width of the print media so that the printhead can remainstationary as the media is transported past the printhead. Such systemsgreatly increase the speed at which printing can occur as the printheadno longer needs to perform a number of swathes to deposit a line of animage, but rather the printhead can deposit the ink on the media as itmoves past at high speeds. Such printheads have made it possible toperform full colour 1600 dpi printing at speeds in the vicinity of 60pages per minute, speeds previously unattainable with conventionalinkjet printers.

Such a pagewidth printhead typically requires high precision and highspeed paper movement and as such the entire print engine (printhead,paper handling mechanisms and control circuitry etc) must be configuredaccordingly to ensure high quality output.

Accordingly, there is a need to provide a print engine having apagewidth printhead that can be readily employed within a standard bodyof a printer unit and is constructed in a manner that ensures that allthe necessary parts of the print engine are configured in a manner thatenables consistent, high speed printing.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, there is provided . . . .

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a front perspective view of a printer unit employing aprint engine according to an embodiment of the present invention;

FIG. 2 shows the printer unit of FIG. 1 with the lid open exposing theprint engine;

FIG. 3 shows a schematic of document data flow in a printing systemaccording to one embodiment of the present invention;

FIG. 4 shows a more detailed schematic showing an architecture used inthe printing system of FIG. 3;

FIG. 5 shows a block diagram of an embodiment of the control electronicsas used in the printing system of FIG. 3;

FIG. 6 shows an exploded perspective view of a print engine according toan embodiment of the present invention;

FIG. 7 shows the print engine of FIG. 6 with cartridge unit inserted inthe cradle unit;

FIG. 8 shows the cradle unit of FIG. 7 with the cover assembly in theclosed position;

FIG. 9 shows a front perspective view of the cartridge unit of FIG. 7;

FIG. 10 shows a front perspective view of the underside of the cartridgeunit of FIG. 9;

FIG. 11 shows an exploded perspective view of the cartridge unit of FIG.7;

FIG. 12 shows an alternative exploded view of the cartridge unit of FIG.7;

FIG. 13 shows a front perspective view of the main body of the cartridgeunit of FIG. 7 with the lid assembly removed;

FIG. 14 shows an exploded front perspective view of the main body ofFIG. 13;

FIG. 15 shows a sectional side view of the main body of FIG. 13;

FIG. 16 shows an example of an ink storage arrangement for use in thecartridge unit of FIG. 9 according to one embodiment;

FIG. 17 shows a cross-sectional view of an ink storage compartmentemploying the ink storage arrangement of FIG. 16

FIG. 18 shows a front perspective view of a printhead assembly suitablefor use with the cartridge unit of FIG. 9;

FIG. 19 shows a front perspective view of the underside of the printheadassembly of FIG. 18;

FIG. 20 shows an exploded view of the printhead assembly of FIG. 18;

FIG. 21 shows a cross-sectional end view of the printhead assembly ofFIG. 18;

FIG. 22 shows a simplified schematic depiction of linked integratedcircuits according to one embodiment of the present invention;

FIG. 23 shows a simplified schematic depiction of two linked integratedcircuits employing a right angled join;

FIGS. 24A and 24B show a schematic depiction of two linked integratedcircuits employing an angled join;

FIG. 25 shows a simplified schematic depiction of two linked integratedcircuits employing a vertical offset join;

FIG. 26 shows a simplified schematic depiction of two linked integratedcircuits employing a sloped placement join;

FIGS. 27A and 27B show a simplified schematic drawing of two linkedintegrated circuits employing a dropped triangle nozzle join;

FIG. 28A shows a magnified perspective view of an integrated circuit asshown in FIGS. 27A and 27B employing a dropped triangle nozzlearrangement;

FIG. 28B shows a magnified perspective view of the join between twointegrated circuits employing the nozzle arrangement of FIG. 28A;

FIG. 28C shows an underside view of the integrated circuit of FIG. 28A;

FIG. 29 shows an exploded perspective view of an alternative printheadassembly according to another embodiment of the present invention;

FIG. 30 shows a partly assembled perspective view of the printheadassembly of FIG. 29;

FIG. 31 shows a plurality of holes being laser drilled into the adhesivelayer of the printhead assembly of FIG. 29;

FIG. 32 shows a plurality of integrated circuits being arranged alongthe surface of the adhesive layer of FIG. 31;

FIGS. 33A-33C show various views of a portion of an ink distributionmember according to a further embodiment of the present invention;

FIG. 34A shows a transparent top view of a printhead assembly employingthe ink distribution member of FIGS. 33A-33C showing in particular, theink passages for supplying ink to the integrated circuits;

FIG. 34B shows an enlarged view of FIG. 34A;

FIG. 35 shows a schematic view of a priming arrangement for priming anink storage compartment of the present invention;

FIG. 36 shows a schematic view of an alternative priming arrangement forpriming an ink storage compartment of the present invention;

FIG. 37 shows a schematic view of the priming arrangement of FIG. 36with the bypass valve in the closed position;

FIG. 38 shows a schematic view of yet another alternative primingarrangement for priming an ink storage compartment of the presentinvention;

FIG. 39 shows a schematic view of the alternative priming arrangement ofFIG. 38 with the bypass valve in a closed position.

FIG. 40 shows yet another alternative arrangement for priming the inkstorage compartment of the present invention, employing a needle whichpasses through the side wall of the compartment;

FIG. 41 shows a vertical sectional view of a single nozzle for ejectingink, for use with the invention, in a quiescent state;

FIG. 42 shows a vertical sectional view of the nozzle of FIG. 41 duringan initial actuation phase;

FIG. 43 shows a vertical sectional view of the nozzle of FIG. 42 laterin the actuation phase;

FIG. 44 shows a perspective partial vertical sectional view of thenozzle of FIG. 41, at the actuation state shown in FIG. 43;

FIG. 45 shows a perspective vertical section of the nozzle of FIG. 41,with ink omitted;

FIG. 46 shows a vertical sectional view of the of the nozzle of FIG. 45;

FIG. 47 shows a perspective partial vertical sectional view of thenozzle of FIG. 41, at the actuation state shown in FIG. 42;

FIG. 48 shows a plan view of the nozzle of FIG. 41;

FIG. 49 shows a plan view of the nozzle of FIG. 41 with the lever armand movable nozzle removed for clarity;

FIG. 50 shows a perspective vertical sectional view of a part of aprinthead chip incorporating a plurality of the nozzle arrangements ofthe type shown in FIG. 41;

FIG. 51 shows a schematic cross-sectional view through an ink chamber ofa single nozzle for injecting ink of a bubble forming heater elementactuator type.

FIGS. 52( a) to 52(c) show the basic operational principles of a thermalbend actuator;

FIG. 53 shows a three dimensional view of a single inkjet nozzlearrangement constructed in accordance with FIG. 22;

FIG. 54 shows an array of the nozzle arrangements shown in FIG. 53;

FIG. 55 shows a schematic showing CMOS drive and control blocks for usewith the printer of the present invention;

FIG. 56 shows a schematic showing the relationship between nozzlecolumns and dot shift registers in the CMOS blocks of FIG. 55;

FIG. 57 shows a more detailed schematic showing a unit cell and itsrelationship to the nozzle columns and dot shift registers of FIG. 56;

FIG. 58 shows a circuit diagram showing logic for a single printernozzle in the printer of the present invention;

FIG. 59 shows a front perspective view of a lid assembly of a cartridgeunit according to an embodiment of the present invention;

FIG. 60 shows a front perspective view of the underside of the lidassembly of FIG. 59;

FIG. 61 shows an exploded front perspective view of the lid assembly ofFIG. 59;

FIG. 62 shows a front perspective view of a capper assembly of acartridge unit according to an embodiment of the present invention;

FIG. 63 shows an exploded front perspective view of the capper assemblyof FIG. 62;

FIG. 64 shows an exploded front perspective view of the underside of thecapper assembly of FIG. 62;

FIG. 65 shows a sectional end view of the capper assembly of FIG. 62;

FIG. 66 shows a sectional perspective view of the capper assemblyoperationally mounted to the cartridge unit of the present invention ina capped state;

FIG. 67 shows a sectional perspective view of the capper assemblyoperationally mounted to the cartridge unit of the present invention inan uncapped state;

FIGS. 68A-68D show various perspective views of the frame structure ofthe cradle unit according to an embodiment of the present invention;

FIG. 69 shows a perspective front view of a cartridge unit supportmember of the cradle unit according to an embodiment of the presentinvention;

FIG. 70 shows a perspective side view of the frame structure of FIGS.68A-68D with the cartridge unit support member of FIG. 69 attachedthereto;

FIGS. 71A-71B show various views of the idle roller assembly of thecradle unit according to one embodiment of the present invention;

FIG. 72 shows a sectional side view of the idle roller assembly of FIGS.71A-71B mounted to the cartridge support member of FIG. 69;

FIGS. 73A and 73B show front and back perspective views of the PCBassembly of the present invention having the control circuitry mountedthereto for controlling the print engine of the present invention;

FIGS. 74A-74C show various views of the PCB assembly of FIGS. 73A and73B mounted between arm supports;

FIGS. 75A and 75B show a support bar assembly for the PCB assembly ofFIGS. 73A and 73B in accordance with one embodiment of the presentinvention;

FIG. 76 shows a perspective view of the support bar assembly of FIGS.75A and 75B assembled to the PCB assembly of FIGS. 74A-74C;

FIGS. 77A and 77B shows perspective views of the assembly of FIG. 76attached to the cradle unit of the present invention;

FIG. 78A-78C show various views of the cover assembly of the cradle unitaccording to an embodiment of the present invention;

FIG. 79 shows a perspective view of the cover assembly as attached tothe cradle unit;

FIG. 80 shows the print engine of the present invention with the coverassembly in an open position;

FIG. 81 shows the print engine of the present invention with the coverassembly in a closed position;

FIG. 82 shows a front perspective view of the push rod assembly inisolation from the cover assembly;

FIG. 83 shows a perspective view of the foot portion of the push rodassembly of FIG. 82;

FIG. 84 shows an ink refill unit according to one embodiment of thepresent invention;

FIG. 85 shows the ink refill unit of FIG. 84 in relation to the printengine of the present invention;

FIG. 86 shows the ink refill unit positioned for refilling ink withinthe print engine as shown in FIG. 85;

FIG. 87 shows the cartridge unit as removed from the cradle unit ofFIGS. 85 and 86;

FIG. 88 shows an underside view of the ink refill unit of FIG. 84;

FIG. 89 illustrates the ink refill unit of FIG. 84 with its lid assemblyremoved;

FIG. 90 shows an exploded view of the various components of the inkrefill unit of FIG. 84;

FIG. 91 illustrates a syringe assembly isolated from the ink refill unitas shown in FIGS. 89 and 90;

FIG. 92 shows an end perspective view of the syringe assembly as shownin FIG. 91;

FIG. 93 illustrates a base assembly isolated from the other componentsof the ink refill unit as shown in FIGS. 89 and 90;

FIGS. 94A-94C show an ink distribution system provided by the ink refillunit positioned on the print engine as shown in FIG. 85;

FIG. 95 shows the ink refill unit with its lid assembly removed inaccordance with an alternative embodiment of a syringe assembly;

FIG. 96 shows an exploded view of the various components of the inkrefill unit as shown in FIG. 95;

FIG. 97 shows a syringe assembly isolated from the ink refill unit asshown in FIG. 95;

FIG. 98 shows an end sectional view of the syringe assembly as shown inFIG. 95;

FIG. 99 shows a base assembly isolated from the other components of theink refill unit as shown in FIGS. 95 and 96;

FIG. 100 shows yet another embodiment of an ink refill unit suitable foruse with the present invention;

FIG. 101 shows an opposite perspective view of the ink refill unit ofFIG. 100;

FIG. 102 shows an underside view of the ink refill unit of FIG. 100;

FIG. 103 shows the ink refill unit of FIG. 100 with its end cap removed;

FIG. 104 shows an exploded view of the various components of the inkrefill unit of FIG. 100;

FIG. 105 shows the working relationship between the internal componentsof the ink refill unit as shown in FIGS. 100 and 104; and

FIG. 106 shows a side sectional view of the ink refill unit of FIG. 100.

DETAILED DESCRIPTION OF EMBODIMENTS

As discussed previously, the present invention resides in a print engine1 that can be readily incorporated into a body of a printer unit 2 toperform the printing functions of the printer unit.

As shown in FIGS. 1 and 2, the printer unit 2, which incorporates theprint engine 1, may be in any form but typically has a media supplyregion 3 for supporting and supplying media 8 to be printed by the printengine, and a media output or collection region 4 for collecting theprinted sheets of media. The printer unit 2 may also have a userinterface 5 for enabling a user to control the operation of the printerunit, and this user interface 5 may be in the form of an LCD touchscreen as shown.

The printer unit 2 typically has an internal cavity 6 for receiving theprint engine 1, and access to the internal cavity may be provided by alid 7 which is hingedly attached to the body of the printer unit 2.

The print engine 1 is configured to be positioned and secured within theprinter unit 2 such that media 8 located in media supply region 3 can befed to the print engine 1 for printing and delivered to the collectionregion 4 for collection following printing. In this regard, the printengine 1 includes media transport means which take the sheets of media 8from the media supply region 3 and deliver the media past the printheadassembly, where it is printed, into the media output tray 4. A pickermechanism 9 is provided with the printer unit 2 to assist in feedingindividual streets of media 8 from the media supply 3 to the printengine 1.

As shown schematically in FIG. 3, in use, the printer unit 2 is arrangedto print documents received from an external source, such as a computersystem 702, onto a print media, such as a sheet of paper. In thisregard, the printer unit 100 includes means which allow electricalconnection between the printer unit 2 and the computer system 702 toreceive data which has been pre-processed by the computer system 702. Inone form, the external computer system 702 is programmed to performvarious steps involved in printing a document, including receiving thedocument (step 703), buffering it (step 704) and rasterizing it (step706), and then compressing it (step 708) for transmission to the printerunit 2.

The printer unit 2 according to one embodiment of the present invention,receives the document from the external computer system 702 in the formof a compressed, multi-layer page image, wherein control electronicsprovided within the print engine 1 buffers the image (step 710), andthen expands the image (step 712) for further processing. The expandedcontone layer is dithered (step 714) and then the black layer from theexpansion step is composited over the dithered contone layer (step 716).Coded data may also be rendered (step 718) to form an additional layer,to be printed (if desired) using an infrared ink that is substantiallyinvisible to the human eye. The black, dithered contone and infraredlayers are combined (step 720) to form a page that is supplied to aprinthead for printing (step 722).

In this particular arrangement, the data associated with the document tobe printed is divided into a high-resolution bi-level mask layer fortext and line art and a medium-resolution contone color image layer forimages or background colors. Optionally, colored text can be supportedby the addition of a medium-to-high-resolution contone texture layer fortexturing text and line art with color data taken from an image or fromflat colors. The printing architecture generalises these contone layersby representing them in abstract “image” and “texture” layers which canrefer to either image data or flat color data. This division of datainto layers based on content follows the base mode Mixed Raster Content(MRC) mode as would be understood by a person skilled in the art. Likethe MRC base mode, the printing architecture makes compromises in somecases when data to be printed overlap. In particular, in one form alloverlaps are reduced to a 3-layer representation in a process (collisionresolution) embodying the compromises explicitly.

As mentioned previously, data is delivered to the printer unit 2 in theform of a compressed, multi-layer page image with the pre-processing ofthe image performed by a mainly software-based computer system 702. Inturn, the print engine 1 processes this data using a mainlyhardware-based system as is shown in more detail in FIG. 4.

Upon receiving the data, a distributor 730 converts the data from aproprietary representation into a hardware-specific representation andensures that the data is sent to the correct hardware device whilstobserving any constraints or requirements on data transmission to thesedevices. The distributor 730 distributes the converted data to anappropriate one of a plurality of pipelines 732. The pipelines areidentical to each other, and in essence provide decompression, scalingand dot compositing functions to generate a set of printable dotoutputs.

Each pipeline 732 includes a buffer 734 for receiving the data. Acontone decompressor 736 decompresses the color contone planes, and amask decompressor decompresses the monotone (text) layer. Contone andmask scalers 740 and 742 scale the decompressed contone and mask planesrespectively, to take into account the size of the medium onto which thepage is to be printed.

The scaled contone planes are then dithered by ditherer 744. In oneform, a stochastic dispersed-dot dither is used. Unlike a clustered-dot(or amplitude-modulated) dither, a dispersed-dot (orfrequency-modulated) dither reproduces high spatial frequencies (i.e.image detail) almost to the limits of the dot resolution, whilesimultaneously reproducing lower spatial frequencies to their full colordepth, when spatially integrated by the eye. A stochastic dither matrixis carefully designed to be relatively free of objectionablelow-frequency patterns when tiled across the image. As such, its sizetypically exceeds the minimum size required to support a particularnumber of intensity levels (e.g. 16×16×8 bits for 257 intensity levels).

The dithered planes are then composited in a dot compositor 746 on adot-by-dot basis to provide dot data suitable for printing. This data isforwarded to data distribution and drive electronics 748, which in turndistributes the data to the correct nozzle actuators 750, which in turncause ink to be ejected from the correct nozzles 752 at the correct timein a manner which will be described in more detail later in thedescription.

As will be appreciated, the components employed within the print engine1 to process the image for printing depend greatly upon the manner inwhich data is presented. In this regard it may be possible for the printengine 1 to employ additional software and/or hardware components toperform more processing within the printer unit 2 thus reducing thereliance upon the computer system 702. Alternatively, the print engine 1may employ fewer software and/or hardware components to perform lessprocessing thus relying upon the computer system 702 to process theimage to a higher degree before transmitting the data to the printerunit 2.

In all situations, the components necessary to perform the abovementioned tasks are provided within the control electronics of the printengine 1, and FIG. 5 provides a block representation of an embodiment ofthe electronics.

In this arrangement, the hardware pipelines 732 are embodied in a SmallOffice Home Office Printer Engine Chip (SoPEC). As shown, a SoPEC deviceconsists of 3 distinct subsystems: a Central Processing Unit (CPU)subsystem 771, a Dynamic Random Access Memory (DRAM) subsystem 772 and aPrint Engine Pipeline (PEP) subsystem 773.

The CPU subsystem 771 includes a CPU 775 that controls and configuresall aspects of the other subsystems. It provides general support forinterfacing and synchronizing all elements of the print engine 1. Italso controls the low-speed communication to QA chips (which aredescribed below). The CPU subsystem 771 also contains variousperipherals to aid the CPU, such as General Purpose Input Output (GPIO,which includes motor control), an Interrupt Controller Unit (ICU), LSSMaster and general timers. The Serial Communications Block (SCB) on theCPU subsystem provides a full speed USB1.1 interface to the host as wellas an Inter SoPEC Interface (ISI) to other SoPEC devices (not shown).

The DRAM subsystem 772 accepts requests from the CPU, SerialCommunications Block (SCB) and blocks within the PEP subsystem. The DRAMsubsystem 772, and in particular the DRAM Interface Unit (DIU),arbitrates the various requests and determines which request should winaccess to the DRAM. The DIU arbitrates based on configured parameters,to allow sufficient access to DRAM for all requesters. The DIU alsohides the implementation specifics of the DRAM such as page size, numberof banks and refresh rates.

The Print Engine Pipeline (PEP) subsystem 773 accepts compressed pagesfrom DRAM and renders them to bi-level dots for a given print linedestined for a printhead interface (PHI) that communicates directly withthe printhead. The first stage of the page expansion pipeline is theContone Decoder Unit (CDU), Lossless Bi-level Decoder (LBD) and, whererequired, Tag Encoder (TE). The CDU expands the JPEG-compressed contone(typically CMYK) layers, the LBD expands the compressed bi-level layer(typically K), and the TE encodes any Netpage tags for later rendering(typically in IR or K ink), in the event that the printer unit 2 hasNetpage capabilities. The output from the first stage is a set ofbuffers: the Contone FIFO unit (CFU), the Spot FIFO Unit (SFU), and theTag FIFO Unit (TFU). The CFU and SFU buffers are implemented in DRAM.

The second stage is the Halftone Compositor Unit (HCU), which dithersthe contone layer and composites position tags and the bi-level spotlayer over the resulting bi-level dithered layer.

A number of compositing options can be implemented, depending upon theprinthead with which the SoPEC device is used. Up to 6 channels ofbi-level data are produced from this stage, although not all channelsmay be present on the printhead. For example, the printhead may be CMYonly, with K pushed into the CMY channels and IR ignored. Alternatively,any encoded tags may be printed in K if IR ink is not available (or fortesting purposes).

In the third stage, a Dead Nozzle Compensator (DNC) compensates for deadnozzles in the printhead by color redundancy and error diffusing of deadnozzle data into surrounding dots.

The resultant bi-level 5 channel dot-data (typically CMYK, Infrared) isbuffered and written to a set of line buffers stored in DRAM via aDotline Writer Unit (DWU).

Finally, the dot-data is loaded back from DRAM, and passed to theprinthead interface via a dot FIFO. The dot FIFO accepts data from aLine Loader Unit (LLU) at the system clock rate (pclk), while thePrintHead Interface (PHI) removes data from the FIFO and sends it to theprinthead at a rate of ⅔ times the system clock rate.

In the preferred form, the DRAM is 2.5 Mbytes in size, of which about 2Mbytes are available for compressed page store data. A compressed pageis received in two or more bands, with a number of bands stored inmemory. As a band of the page is consumed by the PEP subsystem 773 forprinting, a new band can be downloaded. The new band may be for thecurrent page or the next page.

Using banding it is possible to begin printing a page before thecomplete compressed page is downloaded, but care must be taken to ensurethat data is always available for printing or a buffer under-run mayoccur.

The embedded USB 1.1 device accepts compressed page data and controlcommands from the host PC, and facilitates the data transfer to eitherthe DRAM (or to another SoPEC device in multi-SoPEC systems, asdescribed below).

Multiple SoPEC devices can be used in alternative embodiments, and canperform different functions depending upon the particularimplementation. For example, in some cases a SoPEC device can be usedsimply for its onboard DRAM, while another SoPEC device attends to thevarious decompression and formatting functions described above. This canreduce the chance of buffer under-run, which can happen in the eventthat the printer commences printing a page prior to all the data forthat page being received and the rest of the data is not received intime. Adding an extra SoPEC device for its memory buffering capabilitiesdoubles the amount of data that can be buffered, even if none of theother capabilities of the additional chip are utilized.

Each SoPEC system can have several quality assurance (QA) devicesdesigned to cooperate with each other to ensure the quality of theprinter mechanics, the quality of the ink supply so the printheadnozzles will not be damaged during prints, and the quality of thesoftware to ensure printheads and mechanics are not damaged.

Normally, each printing SoPEC will have an associated printer unit QA,which stores information relating to the printer unit attributes such asmaximum print speed. The cartridge unit may also contain a QA chip,which stores cartridge information such as the amount of ink remaining,and may also be configured to act as a ROM (effectively as an EEPROM)that stores printhead-specific information such as dead nozzle mappingand printhead characteristics. The refill unit may also contain a QAchip, which stores refill ink information such as the type/colour of theink and the amount of ink present for refilling. The CPU in the SoPECdevice can optionally load and run program code from a QA Chip thateffectively acts as a serial EEPROM. Finally, the CPU in the SoPECdevice runs a logical QA chip (ie, a software QA chip).

Usually, all QA chips in the system are physically identical, with onlythe contents of flash memory differentiating one from the other.

Each SoPEC device has two LSS system buses that can communicate with QAdevices for system authentication and ink usage accounting. A largenumber of QA devices can be used per bus and their position in thesystem is unrestricted with the exception that printer QA and ink QAdevices should be on separate LSS busses.

In use, the logical QA communicates with the ink QA to determineremaining ink. The reply from the ink QA is authenticated with referenceto the printer QA. The verification from the printer QA is itselfauthenticated by the logical QA, thereby indirectly adding an additionalauthentication level to the reply from the ink QA.

Data passed between the QA chips is authenticated by way of digitalsignatures. In the preferred embodiment, HMAC-SHA1 authentication isused for data, and RSA is used for program code, although other schemescould be used instead.

As will be appreciated, the SoPEC device therefore controls the overalloperation of the print engine 1 and performs essential data processingtasks as well as synchronising and controlling the operation of theindividual components of the print engine Ito facilitate print mediahandling, as will be discussed below.

Print Engine

The print engine 1 is shown in detail in FIGS. 6-8 and consists of twoparts: a cartridge unit 10 and a cradle unit 12.

As shown, the cartridge unit 10 is shaped and sized to be receivedwithin the cradle unit 12 and secured in position by a cover assembly 11mounted to the cradle unit.

The cradle unit 12 is provided with an external body 13 having anchorportions 14 which allow it to be fixed to the printer unit 2 in adesired position and orientation, as discussed above, to facilitateprinting.

In its assembled form as shown in FIG. 8, with cartridge unit 10 securedwithin the cradle unit 12 and cover assembly 11 closed, the print engine1 is able to control various aspects associated with printing, includingtransporting the media past the printhead in a controlled manner as wellas the controlled ejection of ink onto the surface of the passing media.In this regard, the print engine 2 may also include electrical contactswhich facilitate electrical connection with the user interface 5 of theprinter unit 2 to enable control of the print engine 1.

Cartridge Unit

The cartridge unit 10 is shown in detail in FIGS. 9-12. With referenceto the exploded views of FIGS. 11 and 12, the cartridge unit 10generally consists of a main body 20, a lid assembly 21, a printheadassembly 22 and a capper assembly 23.

Each of these parts are assembled together to form an integral unitwhich combines ink storage together with the ink ejection means in acomplete manner. Such an arrangement ensures that the ink is directlysupplied to the printhead assembly 22 for printing, as required, andshould there be a need to replace either or both of the ink storage orthe printhead assembly, this can be readily done by replacing the entirecartridge unit 10.

As is evident in FIGS. 9 and 10, the cartridge unit 10 has facilitiesfor receiving a refill supply of ink to replenish the ink storage whennecessary and the cartridge unit itself carries an integral cappingassembly 23 for capping the printhead when not in use.

Main Body

The main body 20 of the cartridge unit 10 is shown in more detail inFIGS. 13-15 and comprises a moulded plastics body which defines aplurality of ink storage compartments 24 in which the various coloursand/or types of ink are stored. Each of the ink storage compartments 24are separated from one another to prevent mixing of the different inks,as is shown more clearly in FIG. 14, and extend along the length of themain body 20.

There are five ink storage compartments 24 shown, having a square orrectangular shape, with the end compartments being larger than the othercompartments. The larger end compartments are intended to store the inkmore readily consumed during the printing process, such as black ink or(infrared ink in Netpage applications) whilst the smaller compartmentsare intended to store the cyan, magenta and yellow inks traditionallyused in colour printing. The base 25 of each of the ink storagecompartments 24 is provided with a raised portion 26 which surrounds anink outlet 27, through which the ink flows for supply to the printheadassembly 22. The raised portions 26 are typically moulded into the mainbody 20 and act to separate the outlet 27 from the base 25 of the inkstorage compartment 24 to ensure a sufficient flow rate of ink from thecompartment 24.

In this regard, an air barrier/ink filter 28 made from a fine meshmaterial is placed over the ink outlet 27, atop of the raised portions26, thereby leaving a space between the filter and the outlet forreceiving ink. The air barrier/ink filter 28 is formed such that ink canreadily pass through the mesh to the printhead assembly 22 but any airbubbles present in the ink are prevented from passing through.

As shown in FIG. 11, the ink storage compartments 24 are provided withan absorbent material 29 such as a foam for storing the ink. Theabsorbent material 29 is shaped to conform to the shape of the inkstorage compartment 24 and is fitted within the correspondingcompartment to be supported on top of the air barrier/ink filter 28. Inthis arrangement, the lower surface of the absorbent material 29 isseparated from the base 25 of the ink storage compartments via theraised portions 26. The absorbent material 29 acts to absorb inksupplied to the compartment 24 such that the ink is suspended internallywithin. The manner in which ink is supplied to the compartment 24 willbe discussed in more detail later, however it should be appreciated thatthe structure of the absorbent material is such that it contains anumber of open pores which receive and draw in the ink under capillaryaction.

The ink fills the space between the ink filter/air barrier 28 and theoutlet 27 thereby forming an ink dam, which is in fluid communicationwith the ink in the printhead assembly 22 and the ink suspended withinthe absorbent material 29. Due to the nature of the absorbent material29 and the fact that the ink is retained therein under capillary action,a back pressure is created which prevents the ink from freely flowingfrom the compartment 24 and out the nozzles of the printhead assembly22.

Whilst the use of a foam or sponge material as an absorbent material 29which stores the ink therein under capillary attraction forces is wellestablished in the art, due to the nature of such materials, their usemay cause contaminants to be introduced into the stored ink. Thesecontaminants can then make their way to the ink delivery nozzles of theprinthead assembly 22, causing blockages and therefore (possibleirreparable) malfunction of the ink delivery nozzles. Whilstconventional arrangements have typically employed filters and the likein an attempt to protect the nozzles, such filters may themselves becomeblocked due to the presence of particulate material present in the foamor sponge material.

In this regard, in an alternative embodiment, the absorbent material 29may be provided as a block or stack of layers made from a polymermaterial, such as polycarbonate, acrylic, polysulfone, polystyrene,fluoropolymer, cyclic olefin polymer, cyclic olefin copolymer, etc,having the channels 16 formed therein in the form of a micro-capillaryarray, as shown in FIG. 16, with each channel having an average diameterof about 10 microns or less.

In this arrangement, the body of the absorbent material 29, in which themicro-capillary array of the channels 16 is formed, remains stable andrigid at all times. That is, the rigid walls of the channels remainintact during exposure to the ink whereby particulate matter is notintroduced into the ink, unlike the cellular or interlaced arrangementof compressible pores within the conventional foam and sponge materialswhich contribute to contaminant production.

The absorbent material 29 having the channels 16 formed as amicro-capillary array therein can be arranged within the individual inkstorage compartments 24 as shown in FIG. 17. An ink trapping layer 17 isprovided between the ink filter/air barrier 28 and the absorbentmaterial 29. The trapping layer 17 absorbs the supplied ink inmultiple-directions, thus allowing for the ingress of the ink into thelongitudinally orientated channels 16, and in this regard merely acts asa means for presenting the ink to the channels 16. The trapping layer 17may be provided as a foam or sponge material with a thicknesssubstantially less than that of the absorbent material 29, since thefunction of the trapping layer is merely to supply ink to the channels16 of the absorbent material 29 and not to store the ink.

The ink drawn into and stored within the channels 16 is able to pass tothe nozzles of the printhead assembly 22 via the ink trapping layer 17.The use of foam or sponge material in the ink trapping layer 17 mayresult in some particulate contamination occurring in the ink. However,this may be minimized by providing the layer with a thickness anddensity which is just sufficient for absorbing the necessary amount ofink for effective absorption into the channels 16. In any event, sincethe ink is effectively stored only in the absorbent material 29, thecontaminant level that may be produced in the ink trapping layer issignificantly reduced from the levels produced by the conventionalstructures.

A pressed metal chassis 30 is fitted to the underside of the main bodyvia clips 31 formed in the chassis 30 which mate with correspondingclips formed in the main body 20. The pressed metal chassis 30 is shapedto conform to the underside of the main body 20 and includes a pluralityof holes 32 that extend therethrough which are positioned to correspondwith the ink outlets 27 of the ink storage compartments 24 such thatthere is a passage for ink to pass through the chassis 30. The chassis30 provides additional stability to the cartridge unit 10 and includesan edge 33 that extends downwardly from the main body 20 which defines acontact region where the flex printed circuit board 52 of the printheadassembly 22 contacts with corresponding electrical contacts 128 in thecradle unit 12, in a manner which will be described in more detail laterin the description. The chassis 30 also has a plurality of elongaterecesses 34 formed along its length, through which connecting clipsprovided on the printhead assembly 22 pass, for connection to the mainbody 20, as will be described in more detail below.

A seal moulding 35 is attached to the chassis 30 to complete and sealthe ink flow path from the ink storage compartments 24 through thechassis 30. The seal moulding 35 is made from an elastomeric materialand has a plurality of hollow cylindrical inserts 36 formed along itssurface which extend through the holes 32 formed in the chassis 30 andinto the ink outlets 27 of each of the ink storage compartments 24, asshown in FIG. 15. The distal ends of the hollow cylindrical inserts 36abut with the main body 20 to seal the ink outlets 27 and ensure inkflow through the seal moulding 35. The seal moulding 35 is fixed to thesurface of the metal chassis 30 by a lock-fit or a suitable adhesive andacts to provide a substantially planar surface upon which the printheadassembly 22 is attached. The planar surface having a plurality of outletholes 39 provided therein through which ink can flow to the printheadassembly.

As is shown in FIGS. 14 and 15 a flex printed circuit board (PCB) backer37 is attached to the side of the main body 20 via locating studs 38 andextends over the downwardly projecting edge 33 of the chassis 30. Theflex PCB backer 37 is made from a suitable elastomeric material andprovides a backing onto which the flex PCB 52 of the printhead assembly22 is supported following attachment of the printhead assembly 22 to themain body 20. As will be discussed in more detail later in thedescription, the flex PCB 52 from the printhead assembly 22 is providedwith a suitable recess which fits over the locating studs 38 such thatthe electrical dimpled contacts 53 formed on the flex PCB 52 arepositioned over the flex PCB backer 37 and extend outwardly therefrom tocontact suitable electrical contacts 128 provided in the cradle unit 12.This arrangement provides some degree of flexibility in this contactregion such that appropriate electrical contact can be establishedbetween the cradle unit 12 and the cartridge unit 10 to allow thetransmission of data and power therebetween to control the ink ejectingnozzles of the printhead assembly 22. This arrangement also ensures thatthe forces associated with the contact between the cartridge unit 12 andthe cradle unit 10 in this region are carried by the chassis 30 and nottransferred to the printhead assembly 22 which could cause damage to thedelicate printhead integrated circuits.

As shown in FIGS. 13 and 14, the main body 20 also includes a pair ofend supports 40 which extend from the main body 20 in a downwarddirection with respect to the cartridge unit 10. The end supports 40 arearranged such that the seal moulding 35 and the flex PCB backer 37extend along the main body 20 between the two end supports 40. Thepurpose of the end supports 40 will be described later in thedescription.

Printhead Assembly

The printhead assembly 22 is shown in more detail in FIGS. 18 to 21, andis adapted to be attached to the underside of the main body 20 toreceive ink from the outlet holes 39 formed in the planar surface of theseal moulding 35.

As shown more clearly in FIG. 20, the printhead assembly 22 comprises anupper moulding 42, having features which facilitate connection of theprinthead assembly to the main body 20 of the cartridge unit 10. Thesefeatures are in the form of u-shaped clips 43 that project from thesurface of the upper moulding 42. The clips 43 pass through the elongaterecesses 34 provided in the chassis 30 and become captured by lugs (notshown) formed in the main body 20, thereby securing the printheadassembly 22 to the main body 20.

In order to receive ink from the ink storage compartments 24, thesurface of the upper moulding 42 has a plurality of ink inlets 44 whichproject therefrom. The ink inlets 44 are received within the outletholes 39 of the seal moulding 35, when the printhead assembly 22 issecured to the main body 20, and provide a path for the ink to flow tothe printhead integrated circuits for printing. To ensure a sealedconnection, the ink inlets 44 are shaped to fit within the outlet holes39 of the seal moulding 35 and may also be provided with an outercoating that facilitates sealing.

The upper moulding 42 is made from a liquid crystal polymer (LCP) and isbonded to a lower moulding 45 via an adhesive film 46. The lowermoulding 45 is also made from an LCP and has a plurality of channels 47formed along its length. Each of the channels 47 are provided to receiveink from one of the ink storage compartments 24, via an ink inlet 44,and distribute the ink along the length of the printhead assembly 22 forfeeding to the ink delivery nozzles 51 of the printhead assembly 22. Thechannels preferably have a width of 1 mm and are separated by wallshaving a width of 0.75 mm. In the embodiment shown, the lower moulding45 has five channels 47 extending along its length with each of the inkchannels 47 receiving ink from one of the corresponding ink inlets 44.Such an arrangement ensures that the different inks remain separatedthroughout the journey from the individual ink storage compartments 24to the corresponding ink delivery nozzles of the printhead integratedcircuit. In this regard, the adhesive film 46 also acts to seal theindividual ink channels 47 and prevent cross channel mixing of the inkwhen the lower moulding 45 is assembled to the upper moulding 42.

In order to further distribute the ink from the ink channels 47 of thelower moulding 45 to the printhead integrated circuits (ICs) 50, an inkdistribution member 48 is attached to the lower moulding 45 and acts asan interface between the printhead ICs 50 and the ink channels 47 of thelower moulding 45. The purpose of the ink distribution member 48 is toprovide a flow path for ink to flow from the relatively wide channels 47to the relatively small and narrow channels 98 formed on the undersideof the printhead ICs 50 which feed the ink to the individual inkdelivery nozzles 51.

In order to appreciate the manner in which the ink distribution member48 functions to perform millimetric-to-micrometric fluid distribution tothe nozzles of the printhead ICs 50, reference is firstly made to themanner in which the printhead ICs 50 are arranged to form the printingzone of the printhead assembly 22.

As alluded to above, the present invention is related to page-widthprinting and as such the printhead ICs 50 are arranged to extendhorizontally across the width of the passing media to deposit inkdroplets thereon to create an image. To achieve this, individualprinthead ICs 50 are linked together in abutting arrangement across thesurface of the ink distribution member 48 of the printhead assembly 22,as shown simply in FIG. 22. The length of an individual printhead IC 50is around 20-22 mm and as such in order to print an A4/US letter sizedpage, 11-12 individual printhead ICs 50 may be linked together inabutting fashion. Other printing sizes may also be possible and as suchthe number of individual printhead ICs 50 required may vary dependingupon the application.

Each printhead IC 50 has a plurality of individual ink delivery nozzles51 formed therein, the structure and control of which will be describedin more detail later. The nozzles 51 within an individual printhead IC50 are grouped physically to reduce ink supply complexity and wiringcomplexity, and are also grouped logically to minimize power consumptionand to allow a variety of printing speeds.

As mentioned previously, each printhead IC 50 is able to print fivedifferent colours (C, M, Y, K and IR) and contains 1280 ink deliverynozzles 51 per colour, with these nozzles being divided into even andodd nozzles (640 each). Even and odd nozzles for each colour areprovided on different rows on the printhead IC 50 and are alignedvertically to perform true 1600 dpi printing, meaning that the nozzles51 are arranged in 10 rows. The horizontal distance between two adjacentnozzles 51 on a single row is 31.75 microns, whilst the verticaldistance between rows of nozzles is based on the firing order of thenozzles, but rows are typically separated by an exact number of dotlines, plus a fraction of a dot line corresponding to the distance thepaper will move between row firing times Also, the spacing of even andodd rows of nozzles for a given colour must be such that they can sharean ink channel, as will be described below.

The manner in which individual printhead ICs 50 are linked together inabutting fashion may be performed in a variety of ways. As shown in FIG.23, the simplest way to achieve this linkage of the printhead ICs 50 isto form a rectangular join between adjacent ICs 50. However, due to thenature of this rectangular join, it may result in a gap between adjacentnozzles at the join interface which could produce a vertical stripe downthe printed page of media where no ink is deposited, which may beunacceptable in some printing applications.

This may be overcome by providing a sloping join as shown in FIG. 24Awhich provides nozzle overlap at the join interface. As shown by theenlarged view of nozzle rows of a single colour at the interface in FIG.24B, such an arrangement does not produce a visible join along theprinting page as discussed above. In this arrangement, the ICs 50 mustbe perfectly aligned vertically to link in this fashion and as such thismay not be always possible.

To overcome this problem, the ICs 50 may be provided with a verticaloffset, as shown in FIG. 25. This offset can be seen by the verticaloffset between the longitudinal edges of adjacent ICs 50, and thisoffset increases with each join along the length of the printheadassembly 22. For example, if the offset was equivalent to 7 lines ofnozzles per join, then for 11 ICs joined in this manner, there would bea total of 10 joins and 70 additional nozzle lines. This then results inan increase in the lines of data storage required for the printheadassembly. To overcome this, each IC 50 may be placed on a mild slope toachieve a constant number of print lines regardless of the number ofjoins, as shown in FIG. 26. It will be appreciated that in thisarrangement the rows of nozzles on the ICs 50 are aligned, but the IC isplaced in a sloped orientation, such that if all the nozzles were firedat once, the effect would be lots of sloped lines provided on the pageof media, however with the nozzles being fired in the correct orderrelative to the paper movement, a straight line for n dots would beprinted, followed by another straight line for another n dots separatedby 1 line.

Yet another system for linking the ICs 50 in abutting fashion is shownin FIGS. 27A and 27B. In this arrangement, the ICs 50 are shaped attheir ends to link together to form a horizontal line of ICs, with novertical offset between neighboring ICs. A sloping join is providedbetween the ICs which has a 45 degree angle to the upper and lower chipedges. Typically, the joining edge is not straight and has a sawtoothprofile to facilitate positioning, and the ICs 50 are intended to bespaced about 11 microns apart, measured perpendicular to the joiningedge. In this arrangement, the left most ink delivery nozzles on eachrow are dropped by 10 line pitches and arranged in a triangleconfiguration as shown in FIG. 27A and FIGS. 28A and 28B. Thisarrangement provides a degree of overlap of nozzles at the join andmaintains the pitch of the nozzles to ensure that the drops of ink aredelivered consistently along the printing zone. This arrangement alsoensures that more silicon is provided at the edge of the IC 50 to ensuresufficient linkage. Control of the operation of the nozzles is performedby the SoPEC device, however compensation for the nozzles is performedin the printhead, or may also be performed by the SoPEC device,depending on the storage requirements. In this regard it will beappreciated that the dropped triangle arrangement of nozzles disposed atone end of the IC 50 provides the minimum on-printhead storagerequirements. However where storage requirements are less criticalshapes other than a triangle can be used, for example, the dropped rowsmay take the form of a trapezoid.

FIG. 28A shows more clearly the upper surface of a portion of theindividual ICs. As can be seen bond pads 96 are provided along an edgethereof which provide a means for receiving data and or power to controlthe operation of the nozzles from the SoPEC of the cradle unit 12.Fiducials 97 are also provided on the surface of the ICs to assist inpositioning and aligning the ICs 50 with respect to each other. Thefiducials 97 are in the form of markers that are readily identifiable byappropriate positioning equipment to indicate the true position of theIC 50 with respect to a neighbouring IC 50, and are strategicallypositioned at the edges of the IC, proximal the join. As shown in FIG.28B, the fiducials 97 align with corresponding fiducials 97 provided onthe surface of a neighbouring IC 50 to ensure alignment of the ICs toappropriate limits, as discussed above.

The underside of a printhead IC 50 is shown in relation to FIG. 28C. Asshown, along the underside of the IC 50 there are provided a number ofetched channels 98, with each channel 98 in communication with a pair ofrows of nozzles 51. The channels 98 are about 80 microns wide and extendthe length of the IC 50 and include silicon walls 99 formed therein, todivide the channels 98 into portions. The channels are adapted toreceive ink from the ink channels 47 of the lower moulding 45 anddistribute the ink to the pair of rows of nozzles 51 to eject that inkof a specific colour or type. The partitioning of the channels 98 by thesilicon walls 99 ensures that the flow path to the nozzles is not toogreat thereby reducing the likelihood of ink starvation to theindividual nozzles along the length of the IC. In this regard, eachportion feeds approximately 128 nozzles and is individually fed a supplyof ink.

Each of the ICs 50 are positioned and secured to the surface of the inkdistribution member 48. As mentioned previously, the ink distributionmember delivers the ink from the 1 mm wide channels 47 formed in thelower moulding 45 to the 80 micron wide channels 98 formed in theunderside of the printhead ICs 50.

The ink distribution member 48 can be configured in a number of forms.In one embodiment the ink distribution member 48 may be in the form of alaminated structure consisting of a number of layers bonded to oneanother, as described in U.S. Pat. No. 6,409,323 and pending USApplication No. 2004/0113997.

In an alternative embodiment, the ink distribution member 48 may be in atwo-part form comprising an intermediate layer 172 and an adhesive layer173, as shown in FIG. 29. In this arrangement, the intermediate layer172 is arranged to fit over the exposed channels 47 of the lowermoulding 45 to seal the channels 47 and to form a sealed unit with thelower moulding 45. The intermediate layer 172 has a plurality of holes174 formed therethrough along its length each of which are aligned withthe channels 47 and are spaced at regular intervals along the lengththereof.

As shown more clearly in FIG. 30, the holes 174 formed through theintermediate layer 172 which relate to the most central channel 47 ofthe lower moulding 45 are in the form of small diameter holesequi-spaced at intervals along the length of the intermediate layer 172.Larger diameter holes 174 are provided which correspond to the otherchannels 47 of the lower moulding 45, which are displaced laterally fromthe most central channel. These holes 174 are similarly equi-spacedalong the length of the intermediate layer and micro conduits 176 areprovided which extend from the larger diameter holes to terminate at acentral region of the intermediate layer 172, proximal the smallerdiameter holes. These conduits 176 distribute the ink from each of theholes 172 to a central region of the intermediate layer to deliver thedifferent types/colours of ink to the channels 98 formed in theunderside of the integrated circuits 50.

The intermediate layer 172 is also made from a liquid crystal polymer(LCP) which is injection moulded to the appropriate shape andconfiguration. The intermediate layer 172 is bonded to the lowermoulding 45 via a thermal adhesive, such as 3M 816 or Abelflex 5206 or5205, which is applied between the intermediate layer 172 and the lowermoulding 45 and placed in a laminator.

To facilitate placement and to secure the integrated circuits 50 uponthe surface of the intermediate layer 172 a bonding film 175 is appliedto the surface of the intermediate layer 172. The bonding film 175 is inthe form of a laminate polymer film which may be a thermoplastic filmsuch as a PET or Polysulphone film, or it may be in the form of athermoset film, such as those manufactured by AL technologies and RogersCorporation. The bonding film 175 preferably has co-extruded adhesivelayers formed on both sides thereof and is laminated onto the uppersurface of the intermediate layer 172

Following lamination of the bonding layer 175 to the intermediate layer172, holes are drilled through the bonding layer 175 to coincide withthe centrally located small diameter holes 174, and the ends of theconduits 176. This is shown in FIG. 31. These holes provide a separateflow passage through the bonding layer 175 for each of the differenttypes of inks, which feed directly to the appropriate channel portions98 formed on the underside of the integrated circuits 50 for supply tothe ink delivery nozzles 51 associated with each channel portion 98, asdiscussed above. Fiducial locating marks 177 are also drilled into thesurface of the bonding layer to assist in attaching and positioning theICs 50 thereon.

In order to attach the ICs 50 to the surface of the bonding layer 175,the ICs 50 are placed in a die and heated to 170° C. and then pressedinto the bonding layer 175 at 40 psi pressure for about 3 seconds. Thisresults in the ICs 50 being thermally bonded to the intermediate layer172, as shown in FIG. 32. As shown, the fiducial locating marks 177formed in the surface of the bonding layer 175 aid in positioning theICs such that the channels 98 formed in the underside of the ICs 50correctly align with the holes drilled through the bonding layer 175 toprovide a flow path for ink to be fed to the nozzles for printing.

In this embodiment the ink distribution member 48 is in the form of atwo part element containing an intermediate layer 172 which fits overthe channels 47 formed in the lower moulding 45, and a bonding layer 175allowing fluid flow therethrough and which acts to attach the ICs to thesurface of the intermediate layer 172.

In yet another embodiment, the ink distribution member 48 may be in theform of a one-piece element with the ICs being directly attached to itsupper surface. In this regard, rather than providing an intermediatelayer 172 having holes 174 that extend therethrough and conduits 176formed in the upper surface thereof to direct the flow of ink towardsthe central region of the intermediate layer 172, the conduits areformed within the body of the ink distribution member 48 such that theupper surface of the ink distribution member only has small diameterholes formed centrally therein for delivering the ink to theundersurface of the ICs.

The manner in which this is achieved is shown in FIGS. 33A-33C. TheseFigures merely show the manner in which the ink can be directed from oneof the channels 47 of the lower moulding 45, and it will be appreciatedthat the same approach can be similarly applied to deliver ink from theremainder of the channels 47.

As shown, the underside of the ink distribution member 48 is providedwith a plurality of holes or inlets 180 therein, each having a diameterof approximately 1 mm, which corresponds to the width of the channels 47provided in the lower moulding 45. The inlets 180 do not extend throughthe body of the ink distribution member 48, but rather extend into themember 48 to a depth of about a ¾ the thickness of the member 48, asshown in the sectioned view of FIG. 33C.

For the inlets 180 associated with the centre channel 47 of the lowermoulding, an outlet 182, in the form of a 80 micron wide hole, isprovided in the uppermost surface of the ink distribution member 48which extends into the end wall of the inlet 180 to provide a path forthe ink to flow out of the ink distribution member. For the inlets 180associated with the other channels 47 of the lower moulding 45, a tunnel181 is provided from a side wall of the inlet 180 within the inkdistribution member 48 which acts to direct the flow of the ink receivedin the inlet through the body of the ink distribution member 48 to acentral position therein. An outlet 182, as described above, is thenformed on an uppermost side of the ink distribution member to provide apath for the ink present in the tunnel 181 to exit the ink distributionmember at the desired position along the surface of the ink distributionmember. The outlets 182 are essentially 80 microns in width, tocorrespond with the width of the channels 98 provided on the undersideof the integrated circuits 50.

The ink distribution member 48 of this embodiment is made from aphoto-structurable glass-ceramic material, such as Forturan glass. Thesematerials, when exposed to specific levels of pulsed UV laser energydensity (fluence), have a photo-chemical reaction which creates adensity of nanocrystals within the volume thereof, the density of whichis directly proportional to the fluence of the exposed laser beam. Inthis regard, in order to form the desired inlets 180, outlets 182 andtunnels 181 connecting the inlets and outlets, the ink distributionmember 48 is mounted upon a precision XYZ stage for exposure to afocussed laser beam. Various tools may be used to control the size andshape of the critically exposed volume of the glass structure to ensurethat the desired pattern and shape is created within the inkdistribution member. Typical exposure times may vary from 15 minutes to1 hour.

Following exposure the ink distribution member is loaded into an ovenfor thermal treatment to aid in causing crystallisation of exposedregions of the glass. The exposed and thermally treated glass is thenloaded into a mild etchant for around 7 minutes to etch the exposedregions, however the etch time may vary dependant upon the thickness ofthe glass and the depth of the cut. The thermal treatment and etchingsteps may be repeated in order to form the complete ink distributionmember as shown in the figures.

With this arrangement, ink present in the channels 47 of the lowermoulding 45 is drawn into the ink distribution member 48 via inlets 180which are positioned over the channels 47 at regular intervalstherealong. Upon entering the inlets 180, where required, the ink isdirected to a central region of the ink distribution member 48 via theabove mentioned tunnels 181, where the ink can then exit the inkdistribution member 48 via the outlets 182 at a predetermined positionwhich is aligned with the corresponding channels 98 formed in theunderside of the ICs 50.

The ICs 50 are secured to the upper surface of the ink distributionmember 48 to receive the ink therefrom, using spun coated adhesiveapplied to the underside of the IC 50, or by screen printing epoxy onthe upper surface of the ink distribution member 48. In this regard, thefiducials provided on the ICs 50 and on the surface of the inkdistribution member 48 assist in positioning the ICs 50 such that thechannels 98 formed in the underside of the ICs 50 are aligned with theappropriate outlet 182 formed in the upper surface of the member 48 toreceive the correct type/colour of ink.

FIGS. 34A and 34B show the manner in which this is arranged to controlthe delivery of ink from the five channels 47 of the lower moulding 45.These figures provide a top view of the arrangement and for reasons ofclarity, the various elements are shown in outline to indicate themanner in which ink flows between the elements. FIG. 34A is a top viewof the arrangement showing the ICs 50 located centrally upon the inkdistribution member 48. The ink distribution member 48 is in turnsecured to the lower moulding 45 such that the inlets 180 align with therespective channels 47 at regular intervals along the length thereof toreceive ink from the channels 47 for distribution to the ICs 50. Theinlets 180 associated with the central channel 47 are in direct fluidcommunication with an outlet 182, which delivers the ink to theunderside of the ICs 50. The inlets 180 associated with the otherchannels 47 include tunnels 181 formed within the ink distributionmember 48 which are in fluid communication with associated outlets 182disposed remote from the inlets 180 to deliver ink to the underside ofthe ICs 50. As is shown, in this arrangement the outlets 182 arecentrally arranged on the upper surface of the ink distribution memberin a predetermined pattern, with the position of each outlet defining apoint at which ink of a specific colour is delivered to the IC 50.

FIG. 34B is a magnified view of FIG. 34A, showing in detail the mannerin which the ink is supplied to the underside of the ICs 50. Thechannels 98 formed on the underside of the IC 50 are clearly shown, asare the silicon walls 99 provided along the length of the channels 98,which divide the channels 98 into portions. As shown, the ICs 50 arepositioned on the surface of the ink distribution member such that theoutlets 182 align with the channels 98 at the junction of the channelportions, namely at the region where the silicon walls 99 are situated.This then ensures that one outlet 182 supplies ink to two channelportions, allowing a regular spacing of outlets to be achieved along thesurface of the ink distribution member 48.

In the above described embodiment, the ink distribution member 48 is inthe form of a on-piece element thereby overcoming the need to provideseparate layers and reducing the complexity of the system, as sealingbetween layers is no longer required.

Following attachment and alignment of each of the printhead ICs 50 tothe surface of the ink distribution member 48, a flex PCB 52 is attachedalong an edge of the ICs 50 so that control signals and power can besupplied to the bond bads 96 of the ICs 50 to effect printing. As shownmore clearly in FIG. 20, the flex PCB 52 folds around the printheadassembly 22 in an upward direction with respect to the cartridge unit10, and has a plurality of dimpled contacts 53 provided along its lengthfor receiving power and or data signals from the control circuitry ofthe cradle unit 12. A plurality of holes 54 are also formed along thedistal edge of the flex PCB 52 which provide a means for attaching theflex PCB 52 to the locating studs 38 formed on the main body 20, suchthat the dimpled contacts 53 of the flex PCB 52 extends over the flexPCB backer 37. The manner in which the dimpled contacts 53 of the flexPCB 52 contact the power and data contacts 128 of the cradle unit 12 isdescribed later.

A media shield 55 is attached to the printhead assembly 22 along an edgethereof and acts to protect the printhead ICs 50 from damage which mayoccur due to contact with the passing media. The media shield 55 isattached to the upper moulding 42 upstream of the printhead ICs 50 asshown more clearly in FIG. 21, via an appropriate clip-lock arrangementor via an adhesive. When attached in this manner, the printhead ICs 50sit below the surface of the media shield 55, out of the path of thepassing media.

As shown in FIGS. 20 and 21, a space 56 is provided between the mediashield 55 and the upper 42 and lower 45 moulding which can receivepressurized air from an air compressor or the like. As this space 56extends along the length of the printhead assembly 22, compressed aircan be supplied to the space 56 from either end of the printheadassembly 22 and be evenly distributed along the assembly. The innersurface 57 of the media shield 55 is provided with a series of fins 58which define a plurality of air outlets evenly distributed along thelength of the media shield 55 through which the compressed air travels.This arrangement therefore provides a stream of air across the printheadICs 50 in the direction of the media delivery which acts to prevent dustand other particulate matter carried with the media from settling on thesurface of the printhead ICs, which could cause blockage and damage tothe nozzles.

A cross section of the complete printhead assembly 22 is shown in FIG.21. As shown, ink is received from the ink storage compartments 24 viathe ink inlets 44 of the upper moulding 42, which feed the ink directlyinto one of the ink channels 47 of the lower moulding 45. The ink is inturn fed from the ink channels 47 to the ink delivery nozzles 51 of theprinthead ICs 50 by way of the ink distribution member 48.

As shown in FIGS. 20 and 21, the lower moulding 45 is provided with aplurality of priming inlets 59 at one end thereof. Each of the priminginlets 59 communicate directly with one of the channels 47 and provide ameans for priming the printhead assembly 22 and the ink storagecompartments 24 with ink prior to shipment and use. Various ways inwhich the priming is achieved will now be described with reference toFIGS. 35-40.

FIG. 35 is a simplified cross-sectional representation of an ink storagecompartment 24 as described previously. Ink is primed into the absorbentmaterial 29 through the ink outlet 27 which links the compartment 24 tothe channels 47 of the printhead assembly 22. In this regard, the ink issupplied via the priming inlets 59 along the channels 47 of the lowermoulding 45, with each channel 47 in fluid communication with one inkoutlet 27 of an ink storage compartment 24 to deliver ink of a specifictype/colour to that ink storage compartment 24.

Priming of the ink storage compartments 24 is typically performed priorto shipment of the cartridge unit 10 and as such, an ink source can betemporarily attached to the priming inlets 59, wherein upon completionof priming, the priming inlets can be capped/sealed.

As discussed above, priming ink is supplied under pressure to the inkstorage compartment 24 via the ink outlets 27. The priming ink flowsinto the space between the ink filter/air barrier 28 and the outlet 27,and is absorbed into the absorbent material 29 through the inkfilter/air barrier 28. As discussed above, due to the porous nature ofthe absorbent material 29 the ink becomes suspended within the absorbentmaterial due to capillary attraction forces. By keeping the uppersurface of the absorbent material 29 dry and exposed to atmosphericpressure through the vent hole 63, the ink is able to be continuallydrawn into the pores of the absorbent material 29 via capillary action(as shown by arrows B).

As discussed above, ink present in the channels 47 of the lower moulding45 is also supplied to the ink delivery nozzles 51 of the integratedcircuits 50, via the ink distribution member 48. During the abovedescribed priming process, the ink flows to the nozzles 51 to prime theindividual nozzles with ink, and due to the capillary action of theabsorbent material 29 in the ink storage compartments 24, a sufficientbackpressure is established in the ink supply to prevent leakage of theink out of the nozzles 51.

In this regard, the priming operation is ceased before the absorbentmaterial becomes completely saturated and its upper surface becomes wetwith ink, so that the necessary backpressure can be maintained. This maybe controlled by limiting the supply of ink or by more sophisticatedmethods, such as sensing the level of ink within the body. Hydrophobicmaterial may also be used on the surface of the ICs 50 in the vicinityof the nozzles 51 so as to assist in leakage prevention.

In the above-described arrangement, it may be necessary to maintain thepressure of the supplied ink to be below a level which ensures the inkis not ejected through the nozzle outlets 51 during priming.Practically, this situation may increase the required time necessary toprime the cartridge unit 10.

An alternative embodiment for configuring the ink storage compartments24 which provides a means of substantially obviating the need to limitthe ink pressure during priming is illustrated in FIGS. 35 to 39. Inthis embodiment, a bypass fluid path 185 is provided in fluidcommunication with the ink outlet 27.

The bypass fluid path 185 allows the priming ink an additional path intothe ink storage compartment 24 where it can be absorbed by the absorbentmaterial 29. In this regard, the priming ink does not only flow throughthe ink filter air barrier 28 directly into the absorbent material 29,but can also flow into at least a portion of a well region 24A of thecompartment 24, as illustrated by arrows C in FIG. 36. The well region24A is the annular region surrounding the raised portions 26 on the base25 of the compartments where there is a gap between the base 25 of thecompartment 24 and the absorbent material 29. This well region 24Adefines a space where the priming ink can be readily delivered via thebypass fluid path 185.

With this arrangement, by providing more than one path for the ink toenter the ink storage compartment 24, a larger surface area of theabsorbent material 29 is exposed to the priming ink and as such the inkis drawn into the absorbent material more quickly and the supplypressure of the priming ink can be reduced.

The path 185 is provided with a bypass valve 186 which is open duringinitial priming of the cartridge unit 10 and is closed upon completionof the priming operation, as shown in FIG. 37. The bypass valve 186 maybe provided by way of a variety of arrangements and may be eithermanually or automatically controlled. For example, the bypass valve 186may be provided as a manual depression button as illustrated in FIGS. 38and 39.

In this arrangement, the bypass valve 186 is in the form of a button 187provided as a flexible portion of the bottom wall of the path 185. Thebutton 187 may be made from a rubber material and may be connected tothe wall of the path 185 via an annular weakened portion 187 a.Initially, and during priming, the button 187 is positioned as shown inFIG. 38 to allow the priming ink to flow through the path 185. Oncepriming is complete, the path 185 is closed by depressing the button 187into a circular recessed region 188 of the internal wall of the path185. In this regard, the button 187 is captured by the lip 189 andretained therein, thereby blocking the bypass valve 186, as shown inFIG. 39.

It will be appreciated that those skilled in the art will understandthat other bypass valve structures are possible and encompassed by thepresent invention. For example, a simple alternative to the above may beproviding the additional fluid path 185 as a compressible silicon tubeor the like.

The bypass valve 186 may be configured to be irreversibly closed oncethe priming is completed. On the other hand, if refilling of the storagecompartments via the priming inlets of the printhead assembly 22 isdesired, a bypass valve capable of being opened and closed without limitmay be provided.

Another embodiment of the ink storage compartments 24 which provides analternative or additional arrangement for priming the compartments 24with ink is illustrated in FIG. 40.

In this arrangement, a port 190 is provided in at least one of the sidewalls of each compartment 24 in a position below the upper surface ofthe absorbent material 29. The ports 190 are provided for the insertionof a needle 191 from an external ink source syringe or the like (notshown) which penetrates into the absorbent material 29, and throughwhich the priming ink is supplied into the body. The ports 190 areconfigured so that the needle 191 supplies the priming ink towards thelower portion of the absorbent material 29, shown with arrows D in FIG.40, so as to prevent wetting of the uppermost portion of the absorbentmaterial 29, for the reasons discussed above.

Each port 190 is provided with a valve 192 which allows penetration ofthe needle 191 and is sealed when the needle is extracted and at othertimes. For example, the valve 192 may incorporate an elastomeric seal.

In this way, the priming ink is delivered directly to the absorbentmaterial 29 and through capillary force is suspended therein fordelivery to the nozzles of the printhead assembly 22, as shown witharrow E in FIG. 40.

The arrangement of this embodiment may be provided independently ofthose of the above-described embodiments, or may be used in conjunctionwith those arrangements to provide an additional refilling mechanism forthe ink storage compartments 24.

Ink Delivery Nozzles

An example of a type of ink delivery nozzle arrangement suitable for thepresent invention, comprising a nozzle and corresponding actuator, willnow be described with reference to FIGS. 41 to 50. FIG. 50 shows anarray of ink delivery nozzle arrangements 801 formed on a siliconsubstrate 8015. Each of the nozzle arrangements 801 are identical,however groups of nozzle arrangements 801 are arranged to be fed withdifferent colored inks or fixative. In this regard, the nozzlearrangements are arranged in rows and are staggered with respect to eachother, allowing closer spacing of ink dots during printing than would bepossible with a single row of nozzles. Such an arrangement makes itpossible to provide a high density of nozzles, for example, more than5000 nozzles arrayed in a plurality of staggered rows each having aninterspacing of about 32 microns between the nozzles in each row andabout 80 microns between the adjacent rows. The multiple rows also allowfor redundancy (if desired), thereby allowing for a predeterminedfailure rate per nozzle.

Each nozzle arrangement 801 is the product of an integrated circuitfabrication technique. In particular, the nozzle arrangement 801 definesa micro-electromechanical system (MEMS).

For clarity and ease of description, the construction and operation of asingle nozzle arrangement 801 will be described with reference to FIGS.41 to 49.

The ink jet printhead integrated circuit 50 includes a silicon wafersubstrate 8015 having 0.35 Micron 1 P4M 12 volt CMOS microprocessingelectronics is positioned thereon.

A silicon dioxide (or alternatively glass) layer 8017 is positioned onthe substrate 8015. The silicon dioxide layer 8017 defines CMOSdielectric layers. CMOS top-level metal defines a pair of alignedaluminium electrode contact layers 8030 positioned on the silicondioxide layer 8017. Both the silicon wafer substrate 8015 and thesilicon dioxide layer 8017 are etched to define an ink inlet channel8014 having a generally circular cross section (in plan). An aluminiumdiffusion barrier 8028 of CMOS metal 1, CMOS metal 2/3 and CMOS toplevel metal is positioned in the silicon dioxide layer 8017 about theink inlet channel 8014. The diffusion barrier 8028 serves to inhibit thediffusion of hydroxyl ions through CMOS oxide layers of the driveelectronics layer 8017.

A passivation layer in the form of a layer of silicon nitride 8031 ispositioned over the aluminium contact layers 8030 and the silicondioxide layer 8017. Each portion of the passivation layer 8031positioned over the contact layers 8030 has an opening 8032 definedtherein to provide access to the contacts 8030.

The nozzle arrangement 801 includes a nozzle chamber 8029 defined by anannular nozzle wall 8033, which terminates at an upper end in a nozzleroof 8034 and a radially inner nozzle rim 804 that is circular in plan.The ink inlet channel 8014 is in fluid communication with the nozzlechamber 8029. At a lower end of the nozzle wall, there is disposed amoving rim 8010, that includes a moving seal lip 8040. An encirclingwall 8038 surrounds the movable nozzle, and includes a stationary seallip 8039 that, when the nozzle is at rest as shown in FIG. 44, isadjacent the moving rim 8010. A fluidic seal 8011 is formed due to thesurface tension of ink trapped between the stationary seal lip 8039 andthe moving seal lip 8040. This prevents leakage of ink from the chamberwhilst providing a low resistance coupling between the encircling wall8038 and the nozzle wall 8033.

As best shown in FIG. 48, a plurality of radially extending recesses8035 is defined in the roof 8034 about the nozzle rim 804. The recesses8035 serve to contain radial ink flow as a result of ink escaping pastthe nozzle rim 804.

The nozzle wall 8033 forms part of a lever arrangement that is mountedto a carrier 8036 having a generally U-shaped profile with a base 8037attached to the layer 8031 of silicon nitride.

The lever arrangement also includes a lever arm 8018 that extends fromthe nozzle walls and incorporates a lateral stiffening beam 8022. Thelever arm 8018 is attached to a pair of passive beams 806, formed fromtitanium nitride (TiN) and positioned on either side of the nozzlearrangement, as best shown in FIGS. 44 and 49. The other ends of thepassive beams 806 are attached to the carrier 8036.

The lever arm 8018 is also attached to an actuator beam 807, which isformed from TiN. It will be noted that this attachment to the actuatorbeam is made at a point a small but critical distance higher than theattachments to the passive beam 806.

As best shown in FIGS. 41 and 47, the actuator beam 807 is substantiallyU-shaped in plan, defining a current path between the electrode 809 andan opposite electrode 8041. Each of the electrodes 809 and 8041 areelectrically connected to respective points in the contact layer 8030.As well as being electrically coupled via the contacts 809, the actuatorbeam is also mechanically anchored to anchor 808. The anchor 808 isconfigured to constrain motion of the actuator beam 807 to the left ofFIGS. 44 to 46 when the nozzle arrangement is in operation.

The TiN in the actuator beam 807 is conductive, but has a high enoughelectrical resistance that it undergoes self-heating when a current ispassed between the electrodes 809 and 8041. No current flows through thepassive beams 806, so they do not expand.

In use, the device at rest is filled with ink 8013 that defines ameniscus 803 under the influence of surface tension. The ink is retainedin the chamber 8029 by the meniscus, and will not generally leak out inthe absence of some other physical influence.

As shown in FIG. 42, to fire ink from the nozzle, a current is passedbetween the contacts 809 and 8041, passing through the actuator beam807. The self-heating of the beam 807 due to its resistance causes thebeam to expand. The dimensions and design of the actuator beam 807 meanthat the majority of the expansion in a horizontal direction withrespect to FIGS. 41 to 43. The expansion is constrained to the left bythe anchor 808, so the end of the actuator beam 807 adjacent the leverarm 8018 is impelled to the right.

The relative horizontal inflexibility of the passive beams 806 preventsthem from allowing much horizontal movement the lever arm 8018. However,the relative displacement of the attachment points of the passive beamsand actuator beam respectively to the lever arm causes a twistingmovement that causes the lever arm 8018 to move generally downwards. Themovement is effectively a pivoting or hinging motion. However, theabsence of a true pivot point means that the rotation is about a pivotregion defined by bending of the passive beams 806.

The downward movement (and slight rotation) of the lever arm 8018 isamplified by the distance of the nozzle wall 8033 from the passive beams806. The downward movement of the nozzle walls and roof causes apressure increase within the chamber 8029, causing the meniscus to bulgeas shown in FIG. 42. It will be noted that the surface tension of theink means the fluid seal 8011 is stretched by this motion withoutallowing ink to leak out.

As shown in FIG. 43, at the appropriate time, the drive current isstopped and the actuator beam 807 quickly cools and contracts. Thecontraction causes the lever arm to commence its return to the quiescentposition, which in turn causes a reduction in pressure in the chamber8029. The interplay of the momentum of the bulging ink and its inherentsurface tension, and the negative pressure caused by the upward movementof the nozzle chamber 8029 causes thinning, and ultimately snapping, ofthe bulging meniscus to define an ink drop 802 that continues upwardsuntil it contacts adjacent print media.

Immediately after the drop 802 detaches, meniscus 803 forms the concaveshape shown in FIG. 43. Surface tension causes the pressure in thechamber 8029 to remain relatively low until ink has been sucked upwardsthrough the inlet 8014, which returns the nozzle arrangement and the inkto the quiescent situation shown in FIG. 61.

Another type of printhead nozzle arrangement suitable for the presentinvention will now be described with reference to FIG. 51. Once again,for clarity and ease of description, the construction and operation of asingle nozzle arrangement 1001 will be described.

The nozzle arrangement 1001 is of a bubble forming heater elementactuator type which comprises a nozzle plate 1002 with a nozzle 1003therein, the nozzle having a nozzle rim 1004, and aperture 1005extending through the nozzle plate. The nozzle plate 1002 is plasmaetched from a silicon nitride structure which is deposited, by way ofchemical vapor deposition (CVD), over a sacrificial material which issubsequently etched.

The nozzle arrangement includes, with respect to each nozzle 1003, sidewalls 1006 on which the nozzle plate is supported, a chamber 1007defined by the walls and the nozzle plate 1002, a multi-layer substrate1008 and an inlet passage 1009 extending through the multi-layersubstrate to the far side (not shown) of the substrate. A looped,elongate heater element 1010 is suspended within the chamber 1007, sothat the element is in the form of a suspended beam. The nozzlearrangement as shown is a microelectromechanical system (MEMS)structure, which is formed by a lithographic process.

When the nozzle arrangement is in use, ink 1011 from a reservoir (notshown) enters the chamber 1007 via the inlet passage 1009, so that thechamber fills. Thereafter, the heater element 1010 is heated forsomewhat less than 1 micro second, so that the heating is in the form ofa thermal pulse. It will be appreciated that the heater element 1010 isin thermal contact with the ink 1011 in the chamber 1007 so that whenthe element is heated, this causes the generation of vapor bubbles inthe ink. Accordingly, the ink 1011 constitutes a bubble forming liquid.

The bubble 1012, once generated, causes an increase in pressure withinthe chamber 1007, which in turn causes the ejection of a drop 1016 ofthe ink 1011 through the nozzle 1003. The rim 1004 assists in directingthe drop 1016 as it is ejected, so as to minimize the chance of a dropmisdirection.

The reason that there is only one nozzle 1003 and chamber 1007 per inletpassage 1009 is so that the pressure wave generated within the chamber,on heating of the element 1010 and forming of a bubble 1012, does noteffect adjacent chambers and their corresponding nozzles.

The increase in pressure within the chamber 1007 not only pushes ink1011 out through the nozzle 1003, but also pushes some ink back throughthe inlet passage 1009. However, the inlet passage 1009 is approximately200 to 300 microns in length, and is only approximately 16 microns indiameter. Hence there is a substantial viscous drag. As a result, thepredominant effect of the pressure rise in the chamber 1007 is to forceink out through the nozzle 1003 as an ejected drop 1016, rather thanback through the inlet passage 1009.

As shown in FIG. 51, the ink drop 1016 is being ejected is shown duringits “necking phase” before the drop breaks off. At this stage, thebubble 1012 has already reached its maximum size and has then begun tocollapse towards the point of collapse 1017.

The collapsing of the bubble 1012 towards the point of collapse 1017causes some ink 1011 to be drawn from within the nozzle 1003 (from thesides 1018 of the drop), and some to be drawn from the inlet passage1009, towards the point of collapse. Most of the ink 1011 drawn in thismanner is drawn from the nozzle 1003, forming an annular neck 1019 atthe base of the drop 16 prior to its breaking off.

The drop 1016 requires a certain amount of momentum to overcome surfacetension forces, in order to break off. As ink 1011 is drawn from thenozzle 1003 by the collapse of the bubble 1012, the diameter of the neck1019 reduces thereby reducing the amount of total surface tensionholding the drop, so that the momentum of the drop as it is ejected outof the nozzle is sufficient to allow the drop to break off.

When the drop 1016 breaks off, cavitation forces are caused as reflectedby the arrows 1020, as the bubble 1012 collapses to the point ofcollapse 1017. It will be noted that there are no solid surfaces in thevicinity of the point of collapse 1017 on which the cavitation can havean effect.

Yet another type of printhead nozzle arrangement suitable for thepresent invention will now be described with reference to FIGS. 52-54.This type typically provides an ink delivery nozzle arrangement having anozzle chamber containing ink and a thermal bend actuator connected to apaddle positioned within the chamber. The thermal actuator device isactuated so as to eject ink from the nozzle chamber. The preferredembodiment includes a particular thermal bend actuator which includes aseries of tapered portions for providing conductive heating of aconductive trace. The actuator is connected to the paddle via an armreceived through a slotted wall of the nozzle chamber. The actuator armhas a mating shape so as to mate substantially with the surfaces of theslot in the nozzle chamber wall.

Turning initially to FIGS. 52( a)-(c), there is provided schematicillustrations of the basic operation of a nozzle arrangement of thisembodiment. A nozzle chamber 501 is provided filled with ink 502 bymeans of an ink inlet channel 503 which can be etched through a wafersubstrate on which the nozzle chamber 501 rests. The nozzle chamber 501further includes an ink ejection port 504 around which an ink meniscusforms.

Inside the nozzle chamber 501 is a paddle type device 507 which isinterconnected to an actuator 508 through a slot in the wall of thenozzle chamber 501. The actuator 508 includes a heater means e.g. 509located adjacent to an end portion of a post 510. The post 510 is fixedto a substrate.

When it is desired to eject a drop from the nozzle chamber 501, asillustrated in FIG. 52( b), the heater means 509 is heated so as toundergo thermal expansion. Preferably, the heater means 509 itself orthe other portions of the actuator 508 are built from materials having ahigh bend efficiency where the bend efficiency is defined as:

${{bend}\mspace{14mu}{efficiency}} = \frac{{Young}^{\prime}s{\mspace{11mu}\;}{Modulus} \times \left( {{Coefficient}\mspace{14mu}{of}\mspace{14mu}{thermal}\mspace{14mu}{Expansion}} \right)}{{Density} \times {Specific}{\mspace{11mu}\;}{Heat}{\mspace{11mu}\;}{Capacity}}$

A suitable material for the heater elements is a copper nickel alloywhich can be formed so as to bend a glass material.

The heater means 509 is ideally located adjacent the end portion of thepost 510 such that the effects of activation are magnified at the paddleend 507 such that small thermal expansions near the post 510 result inlarge movements of the paddle end.

The heater means 509 and consequential paddle movement causes a generalincrease in pressure around the ink meniscus 505 which expands, asillustrated in FIG. 52( b), in a rapid manner. The heater current ispulsed and ink is ejected out of the port 504 in addition to flowing infrom the ink channel 503.

Subsequently, the paddle 507 is deactivated to again return to itsquiescent position. The deactivation causes a general reflow of the inkinto the nozzle chamber. The forward momentum of the ink outside thenozzle rim and the corresponding backflow results in a general neckingand breaking off of the drop 512 which proceeds to the print media. Thecollapsed meniscus 505 results in a general sucking of ink into thenozzle chamber 502 via the ink flow channel 503. In time, the nozzlechamber 501 is refilled such that the position in FIG. 52( a) is againreached and the nozzle chamber is subsequently ready for the ejection ofanother drop of ink.

FIG. 53 illustrates a side perspective view of the nozzle arrangement.FIG. 54 illustrates sectional view through an array of nozzlearrangement of FIG. 53. In these figures, the numbering of elementspreviously introduced has been retained.

Firstly, the actuator 508 includes a series of tapered actuator unitse.g. 515 which comprise an upper glass portion (amorphous silicondioxide) 516 formed on top of a titanium nitride layer 517.Alternatively a copper nickel alloy layer (hereinafter calledcupronickel) can be utilized which will have a higher bend efficiency.

The titanium nitride layer 517 is in a tapered form and, as such,resistive heating takes place near an end portion of the post 510.Adjacent titanium nitride/glass portions 515 are interconnected at ablock portion 519 which also provides a mechanical structural supportfor the actuator 508.

The heater means 509 ideally includes a plurality of the taperedactuator unit 515 which are elongate and spaced apart such that, uponheating, the bending force exhibited along the axis of the actuator 508is maximized. Slots are defined between adjacent tapered units 515 andallow for slight differential operation of each actuator 508 withrespect to adjacent actuators 508.

The block portion 519 is interconnected to an arm 520. The arm 520 is inturn connected to the paddle 507 inside the nozzle chamber 501 by meansof a slot e.g. 522 formed in the side of the nozzle chamber 501. Theslot 522 is designed generally to mate with the surfaces of the arm 520so as to minimize opportunities for the outflow of ink around the arm520. The ink is held generally within the nozzle chamber 501 via surfacetension effects around the slot 522.

When it is desired to actuate the arm 520, a conductive current ispassed through the titanium nitride layer 517 within the block portion519 connecting to a lower CMOS layer 506 which provides the necessarypower and control circuitry for the nozzle arrangement. The conductivecurrent results in heating of the nitride layer 517 adjacent to the post510 which results in a general upward bending of the arm 20 andconsequential ejection of ink out of the nozzle 504. The ejected drop isprinted on a page in the usual manner for an inkjet printer aspreviously described.

An array of nozzle arrangements can be formed so as to create a singleprinthead. For example, in FIG. 54 there is illustrated a partlysectioned various array view which comprises multiple ink ejectionnozzle arrangements of FIG. 73 laid out in interleaved lines so as toform a printhead array. Of course, different types of arrays can beformulated including full color arrays etc.

The construction of the printhead system described can proceed utilizingstandard MEMS techniques through suitable modification of the steps asset out in U.S. Pat. No. 6,243,113 entitled “Image Creation Method andApparatus (IJ 41)” to the present applicant, the contents of which arefully incorporated by cross reference.

The integrated circuits 50 may be arranged to have between 5000 to100,000 of the above described ink delivery nozzles arranged along itssurface, depending upon the length of the integrated circuits and thedesired printing properties required. For example, for narrow media itmay be possible to only require 5000 nozzles arranged along the surfaceof the printhead assembly to achieve a desired printing result, whereasfor wider media a minimum of 10,000, 20,000 or 50,000 nozzles may needto be provided along the length of the printhead assembly to achieve thedesired printing result. For full colour photo quality images on A4 orUS letter sized media at or around 1600 dpi, the integrated circuits 50may have 13824 nozzles per color. Therefore, in the case where theprinthead assembly 22 is capable of printing in 4 colours (C, M, Y, K),the integrated circuits 50 may have around 53396 nozzles disposed alongthe surface thereof. Further, in a case where the printhead assembly 22is capable of printing 6 printing fluids (C, M, Y, K, IR and a fixative)this may result in 82944 nozzles being provided on the surface of theintegrated circuits 50. In all such arrangements, the electronicssupporting each nozzle is the same.

The manner in which the individual ink delivery nozzle arrangements maybe controlled within the printhead assembly 22 will now be describedwith reference to FIGS. 55-58.

FIG. 55 shows an overview of the integrated circuit 50 and itsconnections to the SoPEC device (discussed above) provided within thecontrol electronics of the print engine 1. As discussed above,integrated circuit 50 includes a nozzle core array 901 containing therepeated logic to fire each nozzle, and nozzle control logic 902 togenerate the timing signals to fire the nozzles. The nozzle controllogic 902 receives data from the SoPEC device via a high-speed link.

The nozzle control logic 902 is configured to send serial data to thenozzle array core for printing, via a link 907, which may be in the formof an electrical connector. Status and other operational informationabout the nozzle array core 901 is communicated back to the nozzlecontrol logic 902 via another link 908, which may be also provided onthe electrical connector.

The nozzle array core 901 is shown in more detail in FIGS. 56 and 57. InFIG. 56, it will be seen that the nozzle array core 901 comprises anarray of nozzle columns 911. The array includes a fire/select shiftregister 912 and up to 6 color channels, each of which is represented bya corresponding dot shift register 913.

As shown in FIG. 57, the fire/select shift register 912 includes forwardpath fire shift register 930, a reverse path fire shift register 931 anda select shift register 932. Each dot shift register 913 includes an odddot shift register 933 and an even dot shift register 934. The odd andeven dot shift registers 933 and 934 are connected at one end such thatdata is clocked through the odd shift register 933 in one direction,then through the even shift register 934 in the reverse direction. Theoutput of all but the final even dot shift register is fed to one inputof a multiplexer 935. This input of the multiplexer is selected by asignal (corescan) during post-production testing. In normal operation,the corescan signal selects dot data input Dot[x] supplied to the otherinput of the multiplexer 935. This causes Dot[x] for each color to besupplied to the respective dot shift registers 913.

A single column N will now be described with reference to FIG. 77. Inthe embodiment shown, the column N includes 12 data values, comprisingan odd data value 936 and an even data value 937 for each of the six dotshift registers. Column N also includes an odd fire value 938 from theforward fire shift register 930 and an even fire value 939 from thereverse fire shift register 931, which are supplied as inputs to amultiplexer 940. The output of the multiplexer 940 is controlled by theselect value 941 in the select shift register 932. When the select valueis zero, the odd fire value is output, and when the select value is one,the even fire value is output.

Each of the odd and even data values 936 and 937 is provided as an inputto corresponding odd and even dot latches 942 and 943 respectively.

Each dot latch and its associated data value form a unit cell, such asunit cell 944. A unit cell is shown in more detail in FIG. 58. The dotlatch 942 is a D-type flip-flop that accepts the output of the datavalue 936, which is held by a D-type flip-flop 944 forming an element ofthe odd dot shift register 933. The data input to the flip-flop 944 isprovided from the output of a previous element in the odd dot shiftregister (unless the element under consideration is the first element inthe shift register, in which case its input is the Dot[x] value). Datais clocked from the output of flip-flop 944 into latch 942 upon receiptof a negative pulse provided on LsyncL.

The output of latch 942 is provided as one of the inputs to athree-input AND gate 945. Other inputs to the AND gate 945 are the Frsignal (from the output of multiplexer 940) and a pulse profile signalPr. The firing time of a nozzle is controlled by the pulse profilesignal Pr, and can be, for example, lengthened to take into account alow voltage condition that arises due to low power supply (in aremovable power supply embodiment). This is to ensure that a relativelyconsistent amount of ink is efficiently ejected from each nozzle as itis fired. In the embodiment described, the profile signal Pr is the samefor each dot shift register, which provides a balance betweencomplexity, cost and performance. However, in other embodiments, the Prsignal can be applied globally (ie, is the same for all nozzles), or canbe individually tailored to each unit cell or even to each nozzle.

Once the data is loaded into the latch 942, the fire enable Fr and pulseprofile Pr signals are applied to the AND gate 945, combining to thetrigger the nozzle to eject a dot of ink for each latch 942 thatcontains a logic 1.

The signals for each nozzle channel are summarized in the followingtable:

Name Direction Description D Input Input dot pattern to shift registerbit Q Output Output dot pattern from shift register bit SrClk InputShift register clock in - d is captured on rising edge of this clockLsyncL Input Fire enable - needs to be asserted for nozzle to fire PrInput Profile - needs to be asserted for nozzle to fire

As shown in FIG. 58, the fire signals Fr are routed on a diagonal, toenable firing of one color in the current column, the next color in thefollowing column, and so on. This averages the current demand byspreading it over 6 columns in time-delayed fashion.

The dot latches and the latches forming the various shift registers arefully static in this embodiment, and are CMOS-based. The design andconstruction of latches is well known to those skilled in the art ofintegrated circuit engineering and design, and so will not be describedin detail in this document.

The nozzle speed may be as much as 20 kHz for the printer unit 2 capableof printing at about 60 ppm, and even more for higher speeds. At thisrange of nozzle speeds the amount of ink than can be ejected by theentire printhead assembly 22 is at least 50 million drops per second.However, as the number of nozzles is increased to provide forhigher-speed and higher-quality printing at least 100 million drops persecond, preferably at least 500 million drops per second and morepreferably at least 1 billion drops per second may be delivered. At suchspeeds, the drops of ink are ejected by the nozzles with a maximum dropejection energy of about 250 nanojoules per drop.

Consequently, in order to accommodate printing at these speeds, thecontrol electronics must be able to determine whether a nozzle is toeject a drop of ink at an equivalent rate. In this regard, in someinstances the control electronics must be able to determine whether anozzle ejects a drop of ink at a rate of at least 50 milliondeterminations per second. This may increase to at least 100 milliondeterminations per second or at least 500 million determinations persecond, and in many cases at least 1 billion determinations per secondfor the higher-speed, higher-quality printing applications.

For the printer unit 2 of the present invention, the above-describedranges of the number of nozzles provided on the printhead assembly 22together with the nozzle firing speeds and print speeds results in anarea print speed of at least 50 cm² per second, and depending on theprinting speed, at least 100 cm² per second, preferably at least 200 cm²per second, and more preferably at least 500 cm² per second at thehigher-speeds. Such an arrangement provides a printer unit 2 that iscapable of printing an area of media at speeds not previously attainablewith conventional printer units.

Lid Assembly

The lid assembly 21 of the cartridge unit 10 is shown in FIGS. 59-61.The lid assembly 21 is arranged to fit over the main body 20, therebysealing each of the ink storage compartments 24. As such, the lidassembly 21 is shaped to conform to the shape of main body 20 and isattached to the main body via ultrasonic welding, or any other suitablemethod which provides a sealed connection.

The outer surface 60 of the lid assembly 21 is provided with a number ofink refill ports 61, for receiving ink from a refill unit 200 and fordirecting the refill ink into one of the ink storage compartments 24 ofthe main body 20. In the embodiment shown in FIG. 59, there are five inkrefill ports 61 provided, with each of the refill ports being in fluidcommunication with one of the five ink storage compartments 24 tofacilitate refilling of the associated compartments with ink.

The ink refills ports 61 are in the form of holes extending through thelid assembly 11 and each hole is provided with a valve fitting 62 madefrom an elastomeric moulding. The valve fittings 62 act to seal theports 61 during non refill periods and provide a means for interactingwith an outlet of the ink refill unit 200 to ensure controlled transferof ink between the ink refill unit 200 and the ink storage compartment24. In this regard, when an ink refill unit 200 is not in communicationwith the ink refill ports 61 the valve fittings 62 seal the ink refillports, and when the ink refill unit 200 is in communication with the inkrefill ports, the valve fittings permits transfer of ink from the inkrefill unit through the ink refill ports. The manner in which this isachieved is described later in the description.

The outer surface 60 of the lid assembly 21 also includes a ventingarrangement which provides air venting of each ink storage compartment24. The venting arrangement consists of individual vent holes 63 whichextend into the individual ink storage compartments 24 and channels 64which extend from the vent holes 63 to the edge of the lid assembly 21.The channels 64 are preferably etched into the outer surface 60 of thelid assembly and assume a tortuous path in the passage from the ventholes 63 to the edge of the lid assembly.

As shown in FIG. 61, a film 65 is placed over the outer surface 60 ofthe lid assembly and includes holes 66 formed therein which fit aroundthe ink refill ports 61. The film 65 may be an adhesive film such as asticker/label or the like which may also have printed thereoninstruction information to assist the user in handling the cartridgeunit 10. When applied to the surface of the lid assembly 21, the filmsits atop the etched channels 64 formed in the outer surface 60, therebyenclosing the venting passage from the vent hole 63 to the edge of thelid assembly 21 which enables the ink storage compartment to breathe viathe tortuous path.

The underside of the lid assembly 21 is shown in more detail in FIG. 60and includes flow channels 67 extending from the underside of the inkrefill ports 61 to direct the refill ink into the appropriate inkstorage compartment 24. As shown in FIG. 61, a weld membrane 68 iswelded to the underside of the ink refill ports 61 and the flow channels67 to form sealed delivery passages along which the ink passes en routeto each of the ink storage compartments 24.

The underside of the lid assembly 21, also includes moulded features orridges 69 which extend into the ink storage compartments 24 when the lidassembly 21 is sealed to the main body 20. These moulded features orridges 69 ensure that an air gap is formed above the absorbent material29 for venting via the vent hole 63 to assist the absorbent material 29to function to absorb the ink and retain the ink suspended therein undercapillary action.

As shown in FIGS. 59 and 60, extending downwardly from the outer surface60 of the lid assembly 21 are a pair of guide walls 70. The guide walls70 assist in locating the lid assembly 21 on the main body 20 duringassembly. The guide walls 70 also have a recessed portion 71 formedtherein which acts as a hand grip to assist in handling the cartridgeunit during use.

As shown more clearly in FIG. 59, the guide wall 70 that extends alongthe face of the main body 20 proximal the printhead assembly 22 alsoincludes a series of holes 72 in a lower edge thereof. These holes 72are arranged to align with and receive the locating studs 38 provided onthe main body 20 onto which the flex PCB backer 37 and the flex PCB 52of the printhead assembly 22 are attached. In this arrangement, when thelid assembly 21 is fixed to the main body 20, a portion of the flex PCB52 of the printhead assembly 22 is sandwiched between the guide wall 70and the flex PCB backer 37, thereby acting to help retain the flex PCB52 in position.

Capper Assembly

As discussed previously and shown in FIGS. 11 and 12, the main body 20of the cartridge unit 10 is provided with downwardly projecting endsupports 40. The end supports 40 are integral with the main body 20 andare arranged such that the printhead assembly 22 is positioned betweenthe end supports. Each of the end supports 40 are configured to receivethe capping assembly 23 and as such have retaining projections 73 formedon their surfaces to retain the capping assembly 23 in position.

The capping assembly 23 is shown in more detail in FIGS. 62 to 67, andgenerally consists of a capper chassis 74 which receives the variouscomponents of the capping assembly 23 therein. The capper chassis 74 isin the form of an open ended channel having a pair of upwardly extendingtongue portions 75 at its ends which are shaped to fit over the endsupports 40 of the main body and engage with the retaining projections73 provided thereon to secure the capper assembly 23 in position. Thecapper chassis 74 essentially retains the parts of the capper assembly23 therein, and is made from a suitable metal material, having rigidityand resilience, such as a pressed steel plate.

The base of the capper chassis 74 is shown more clearly in FIG. 64 andincludes a centrally located removed portion 76 and spring arms 77extending from either side of the removed portion 76 towards the tongueportions 75. The spring arms 77 are hingedly fixed to the chassis 74 atthe region proximal the removed portion, and are biased inwards of thecapper chassis. The spring arms 77 may be made from the same material asthe chassis and formed by removing material from the chassis pressingthe arms from the base of the chassis. Whilst the spring arms 77 areshown as being integral with the chassis 74, they may be provided as aseparate insert which may be inserted into the open channel of thechassis 74, as would be appreciated by a person skilled in the art.

A rigid insert 78 is provided to fit within the chassis 74 to provideadded rigidity to the capper assembly 23. In this regard the insert 78is made from moulded steel and forms an open u-shaped channel. A lowercapper moulding 79 is located within the insert 78 and retained withinthe insert via engagement of a number of lugs 80 formed along the sidesof the lower capper moulding 79 with corresponding holes 81 provided inthe sides of the insert 78. The lower capper moulding 79 is made from asuitable plastic material and forms a body having closed ends and anopen top. The ends of the lower capper moulding 79 are provided with airvents 82 which provide a means for air to enter the capper assembly andventilate the capper assembly.

The base of the lower capper moulding is provided with a pair ofcentrally located projections 83 which are received within slots 84formed in the base of the rigid insert 78. The projections 83 extendthrough the rigid insert 78, beyond its outer base surface to define aregion for receiving an electromagnetic button 85, which is spot weldedto the outer base surface of the rigid insert 78 between the projections83. The purpose of the electromagnetic button 85 will be discussed inmore detail later in the description; however it should be appreciatedthat the electromagnetic button 85 can be made of any material which iscapable of experiencing magnetic attraction forces.

A strip of absorbent media 86 is provided to fit within the lowercapping moulding 79, and may be made from any type of material capableof absorbing and retaining ink therein, such as urethane foam or thelike. The absorbent media 86 is shaped to fit within the lower cappermoulding 79 and includes a stepped portion 87 which projects above thelower capper moulding 79 and extends centrally along the length of theabsorbent media 86, as is shown more clearly with regard to FIGS. 63 and65.

An upper capper moulding 88 is then provided to fit over the lowercapper moulding 79 and the absorbent media 86. The upper capper moulding88 has essentially two portions, a lower portion 89 which seals alongthe edges of the lower capper moulding 79 to retain the absorbent media86 therein, and an upper portion 90 which essentially conforms to theshape of the stepped portion 87 of the absorbent media 86. The lowerportion 89 is made from a rubber or plastics material and has an edgeportion which sits along the upper edge of the lower capping moulding 79and which is attached thereto by an ultrasonic weld or any othersuitable attachment means. The upper portion 90 has an open uppersurface and is made from a dual shot elastomeric material. The openupper surface is in the form of a rim portion 91 that extends beyond theabsorbent media 86 and defines a perimeter seal for sealing theintegrated circuits 50 of the printhead assembly 22, as is shown inrelation to FIG. 65. The space formed between the upper edge of the rimportion 91 and the absorbent media 86 is the space which seals theintegrated circuits 50 of the printhead assembly 22.

In this arrangement, the upper capper moulding 88, absorbent media 86,lower capper moulding 79 and the rigid insert 78 form a unit which isadapted to fit within the capper chassis 74. In order to secure the unitin place, a retainer element 92 is provided which fits over the uppercapping moulding 88 and is secured to the chassis 74 as shown in FIG.62.

The retainer element 92 is essentially in the form of an open endedchannel which fits over the upper capper moulding 88 and encloses thecomponents therein. A slot 93 is formed in the upper surface of theretainer element 92 through which the upper portion 90 of the uppercapper moulding 88 can protrude and the slot is shaped to conform to theshape of the upper portion 90 of the upper capper moulding 88, as isshown in FIG. 65. The upper surface of the retainer element 92 is curvedand acts as a media guide during printing, as will be described in moredetail later. The retainer element 92 is fixed to the chassis via asnap-fit arrangement whereby lugs 94 formed in the retainer element 92are received in recesses 95 provided in the chassis 74. When assembledin this manner, the components of the capper assembly 23 are containedwithin the retainer element 92 and the chassis 74, and theelectromagnetic button 85 secured to the rigid insert 78 is aligned withthe centrally located removed portion 76 of the chassis.

Upon assembly and attachment of the capper assembly 23 to the endsupports 40 of the main body 20, due to the presence of the spring arms77 extending inwardly from the base of the chassis 74, the rigid insert78 which contains the lower capper moulding 79, absorbent media 86 andthe upper capper moulding 88 therein, is supported on the spring arms 77and is raised from the base of the chassis 74. This state is shown inFIGS. 62 and 65, and in this state the upper portion 90 of the uppercapper moulding 88 protrudes through the slot 93 provided in theretainer element 92. This state is the capping state, whereby the upperrim portion 91 of the upper capper moulding 88 contacts the printheadassembly 22 and acts as a perimeter seal around the printhead integratedcircuits 50, sealing them within the confined space of the capperassembly 23. In the capping state, the nozzles 51 of the printheadintegrated circuits 50 may fire and spit ink into the absorbent material86. The absorbent material 86, is typically retained in a moist state atall times, such that when the integrated circuits are in the cappingstate, the nozzles are sealed in a moist environment which prevents inkfrom drying in the nozzles of the integrated circuits and blocking thenozzles.

In order to perform printing, the capper assembly 23 must be moved froma capping state to a printing state. This is achieved by causing therigid insert 78 to act against the spring arms 77 of the chassis 74 andmove in a downwards direction, towards the base of the chassis 74. Thismovement is caused by applying an electromagnetic force in the vicinityof the base of the capper assembly 23, proximal the centrally locatedremoved portion 76. The activation of the electromagnet force attractsthe electromagnet button 85 fixed to the underside of the rigid insert78, thereby causing the rigid insert, which contains the lower cappermoulding 79, absorbent media 86 and the upper capper moulding 88therein, to move in a downward direction with respect to the printheadassembly 22. The centrally located removed portion 76 of the base of thechassis 74 allows the electromagnet button 85 to be fully retractedagainst the spring arms 77 towards the source of the electromagneticforce. This in turn causes the upper rim portion 91 of the upper cappingmoulding 88 to retract into the retainer element 92 such that it isflush with the outer surface of the retainer element 92 and does notprotrude therefrom. It will be appreciated that the retainer element 92does not move and is fixed in position. Such a state is referred to asthe printing state, and in this state there is a gap formed between theretainer element 92 and the printhead assembly 22 through which themedia can pass for printing. In the printing state, the retainer element92 acts as a media guide and the media contacts the retainer element andis supported on the surface of the retainer element as it passes theprinthead assembly for printing.

FIGS. 66 and 67 show the cartridge unit 10 in the capping state and theprinting state respectively. It will be appreciated that due to theaction of the spring arms 77, the capping state is the relaxed state ofthe capper assembly 23 and whenever printing is not occurring thecartridge unit 10 is in the capping state. In this regard, the cartridgeunit 10 is packaged and shipped in the capping state. As such, to movethe cartridge unit 10 into a printing state, power must be supplied toan electromagnet, which is located in the cradle unit 12 as describedlater, to cause the upper capper moulding 88 to retract into theretainer element 92. In the event of power failure or cessation of powerto the printer unit, the electromagnetic force is removed, and thecapper assembly 23 returns to the capping state under action of thespring arms 77, thereby protecting the printhead integrated circuits 50against prolonged periods of exposure to drying air.

Cradle Unit

The cradle unit 12 is shown in relation to FIGS. 6-8 and generallyconsists of a main body 13 which defines an opening for receiving thecartridge unit 10, and a cover assembly 11 adapted to close the openingto secure the cartridge unit 10 in place within the cradle unit 12.

The main body 13 of the cradle unit 12 includes a frame structure 101 asshown in FIGS. 68A-68D. The frame structure 101 generally comprises twoend plates 102 and a base plate 103 connecting each of the end plates102. As mentioned previously, each of the end plates 102 is providedwith anchor portions 14 formed the base thereof to enable the printengine 1 to be secured in position within the printer unit 2. A driveroller 104 and an exit roller 105 are mounted between the end plates 102via mounting bearings 106 and are separated a distance to accommodatethe cartridge unit 10 when the print engine 1 is fully assembled. Thedrive roller 104 and the exit roller 105 are each driven by a brushlessDC motor 107 which is mounted to one of the end plates 102 and driveseach of the drive and exit rollers via a drive mechanism 108, such as adrive belt. Such a system ensures that both the drive roller 104 and theexit roller 105 are driven at the same speed to ensure a smooth andconsistent passage of the media through the print engine 1.

An electromagnet assembly 109 is mounted to the underside of the baseplate 103 in a central position as shown most clearly in FIGS. 68C and68D. The purpose of the electromagnet assembly 109 is to actuate thecapper assembly 23 of the cartridge unit 10, as previously discussed. Ahole 110 is provided in the base plate 103 around the electromagnetassembly 109 to facilitate communication with the electromagnet button85 on the capper assembly 23.

A refill solenoid assembly 111 is mounted to the other end plate 102,opposite the DC motor 107, and is provided to operate a refill unit 200to refill the cartridge unit 10 with refill ink, as will be describedlater. The refill solenoid assembly 111 is positioned such that anactuator arm 112 extends beyond the upper edge of the end plate 102, thepurpose of which will become apparent later in the description.

Cartridge unit guides 113 are also mounted to the interior surfaces ofeach of the end plates 102. The guides are located at the rear of thecradle unit 12 and assist in positioning the cartridge unit 10 withinthe cradle unit 12 to ensure that removal and replacement of thecartridge unit 10 is a simple process. To further accommodate thecartridge unit 10, a cartridge unit support member 114 is mountedbetween the end plates 102 at the front of the cradle unit 12. Thecartridge unit support member 114 is shown in more detail in FIG. 69,and is in the form of a shaped plate fixed to the front portion of thecradle unit 12. The cartridge unit support member 114 has a pair ofclips 115 which fit into recesses 116 formed in the end plates 102 andhas further anchor points 117 which enable the cartridge unit supportmember to be fixed to the end plates 102, via screws or the like, toform a surface upon which the cartridge unit 10 can be received andsupported. The cartridge unit support member 114 together with thecartridge unit guides 113, defines a space 118 for receiving thecartridge unit 10 therein which conforms to the shape of the cartridgeunit 10, as shown in FIG. 70.

An idle roller assembly 119 is fixed to the cartridge unit supportmember 114 and includes a plurality of roller wheels 120 which arepositioned to contact the surface of the drive roller 104 and rotatetherewith. The idle roller assembly 119 is shown in FIGS. 71A and 71Band comprises a curved multi-sectioned plate 121 with each section ofthe plate having a pair of roller wheels 120 provided at its distal end.Each section of the plate 121 is spring loaded against the surface ofthe cartridge unit support member 114 via a suitable spring means 122,to allow the roller wheels 120 to move with respect to the surface ofthe drive roller 104 to accommodate print media therebetween. The idleroller assembly 119 is attached to the under-surface of the cartridgeunit support member 114 via clips 123 which are received incorresponding slots 124 formed in the cartridge unit support member 114,as is shown in FIG. 72. Such an arrangement ensures that the media thatis presented to the print engine 1 from the picker mechanism 9 of theprinter unit 2, is gripped between the drive roller 104 and the idleroller assembly 119 for transport past the printhead assembly 22 of thecartridge unit 10 for printing.

The control electronics for the print engine which controls theoperation of the integrated circuits 50 of the printhead assembly 22, aswell as the operation of the drive roller 104 and exit roller 105 andother related componentry, is provided on a printed circuit board (PCB)125 as shown in FIGS. 73A and 73B. As can be seen, one face of the PCB125 contains the SoPEC devices 126 and related componentry 127 forreceiving and distributing the data and power received, as will bediscussed later, whilst the other face of the PCB includes rows ofelectrical contacts 128 along an edge thereof which provides a means fortransmitting the power and data signals to the printhead assembly 22 ina manner to be described below.

The PCB 125 is mounted between two arms 129, with each of the armshaving a claw portion 130 to receive the PCB 125 in position, as shownin FIGS. 74A-74C. Each arm 129 is configured to have a substantiallystraight edge 131 and an angled edge 132 having a protrusion 133 formedthereon. The PCB 125 is positioned between the arms 129 such that theface of the PCB having the electrical contacts 128 formed along thelower edge thereof extends between the substantially straight edges 131of the arms 129.

The upper region of each of the arms 129 includes an upwardly extendingfinger portion 134 and a spring element 135 is provided for each of thearms 129, the purpose of the finger portion 134 and the spring element135 will be discussed in more detail later.

In order to provide stability to the PCB 125 as it is mounted betweenthe two arms 129, a support bar 136 is attached to the assembly whichacts along the bottom edge of the PCB 125, on the face that contains theSoPEC devices 126 and the related componentry 127. This support bar 136is shown in FIGS. 75A-75B and consists of a curved plate 137 made from asuitable material such as steel which has appropriate strength andrigidity properties. The support bar 136 has a contact edge 138 which isarranged to contact the surface of the PCB 125, along its bottom edgeopposite the electrical contacts 128. The contact edge 138 has a pair ofattachment points 139 at its ends which allow the support bar 136 to besecured to the PCB 125 via screws or other suitable attachment means.Locating projections 140, are also provided to mate with appropriatelocating holes in the PCB 125 to assist in correctly position thesupport bar 136 in place. The contact edge 138 includes an electricalinsulator coating 141 along its length which performs the contactbetween the support bar 136 and the PCB 125. It will be appreciated thatthe support bar 136 contacts the surface of the PCB 125 along its' loweredge and provides backing support to the electrical contacts 128 whenthey come into contact with the corresponding dimple contacts 53provided on the flex PCB 52 of the printhead assembly 22.

The support bar 136 also includes a relatively straight portion 142which extends substantially horizontally from the contact edge 138. Thestraight portion 142 includes a pair of tabs 143 that extendlongitudinally from its ends to engage with corresponding slots 144provided in the arms 129 to further secure the support bar 136 inposition. A plurality of star wheels 145 is also provided along thelength of the straight portion 142 in a staggered arrangement. The starwheels 145 are secured within slots 146 formed in the straight portion142 and are provide on spring loaded axles 147 which permits relativemovement of the star wheels 145 with respect to the straight portion ofthe support bar 146. The star wheels 145 are provided to contact thesurface of the exit roller 105 to assist in gripping and removing theprinted media from the print engine 1, as will be discussed below. FIG.76 shows the support bar 136 attached to the PCB 125 and arms 129.

The arms 129 are attached to a bottom portion of end plates 102 at thepivot point 148 via a screw arrangement as shown in FIGS. 77A and 77B.In this arrangement the arms 129, and subsequently the PCB 125 andsupport bar 136, is able to pivot about the pivot point 148 between anopen position wherein the contacts 128 on the PCB 125 are remote fromthe dimpled contacts 53 on the flex PCB 52 of the cartridge unit 22, anda closed position where the contacts 128 on the PCB 125 are in pressingcontact with the dimpled contacts 53 on the flex PCB 52 of the cartridgeunit 22. As clearly shown, upon attachment of the arms 129 to the endplates 102, the star wheels 145 are in contact with the surface of theexit roller 105, to capture the sheet of media therebetween for removalof the sheet from the print engine 1 to a collection area 4 forcollection.

The cover assembly 11, as shown in FIGS. 78A-78C, is attached to theupper portion of the end plates 102 via pivot pins 150 which arereceived in holes 151 formed in the upper portion of the end plates 102.The cover assembly 11 is made from a moulded plastic material and thepivot pins 150 are formed proximal to a rear edge of the cover assembly11 during the moulding process. The pivot pins 150 allow the coverassembly 11 to pivot about the end plates 102 between a closed position,where the cartridge unit 10 is secured within the cradle unit 12, and anopen position, where the cartridge unit 10 can be removed from thecradle unit 12 and replaced. A latch 152 is provided in a front edge 153of the cover assembly 11. The latch 152, has a flexible clip element 154which is received within a recess 155 provided in the cartridge unitsupport member 114 when the cover assembly 11 is in the closed position,as shown in FIG. 81. The flexible clip element 154 is spring loaded viaa spring element (not shown) such that the clip element 154 can bereadily depressed to release engagement between it and the recess 155provided in the cartridge unit support member 114 so that the coverassembly 11 can be pivoted into an open position, as shown in FIG. 80.

Positioned adjacent the pivot pins 150, on the inside of the coverassembly 11, are a pair of posts 156. The posts 156 are arrangedsubstantially alongside the pivot pins 150, towards the front edge 153of the cover assembly 11. The posts 156 are configured such that theyare a greater length than the pivot pins 150 and hence extend inwardly agreater distance, to contact the spring element 135 of the arms 129which support the PCB 125.

In this regard, the act of opening and closing the cover assembly 11also performs the function of bringing the contacts 128 provided on thesurface of the PCB 125, into contact with the corresponding dimpledcontacts 53 provided on the flex PCB 52 of the printhead assembly 22. Toachieve this, the cover assembly 11 and the arms 129 are arranged asshown in FIG. 79.

As shown, the cover assembly 11 is attached to the end plates 102 suchthat the posts 156 extend between the upwardly extending finger portion134 and the spring element 135 at each end thereof. When the coverassembly 11 is moved to the open position, as shown in FIG. 80, theposts 156 act against the upwardly extending finger portion 134 of thearms 129 causing the arms 129, and the PCB 125, to pivot away fromcontact with the dimpled contacts 53 of the flex PCB 52 of the cartridgeunit 22. This movement is due to the swing action of the cover assembly11 when opened which in turn causes the posts 156 to move in an arcuatedirection towards the rear of the print engine 1. When the coverassembly 11 moves to the closed position as shown in FIG. 81, the coverassembly 11 pivots about the pivot pins 150, causing the posts 156 tomove in an arcuate direction towards the front of the print engine 1. Asthe posts 156 move, they contact the upright portion of the springelement 135, causing the PCB 125 and the arms 129 to pivot forward. Thespring element 135 has considerable rigidity to transfer the forceexerted upon it by the posts 156 into forward movement of the PCB 125and arms 129 which results in the contacts 128 on the outward lowerportion of the PCB 125 to contact the corresponding dimpled contacts 53provided on the flex PCB 52 of the cartridge unit 10, which ispositioned and supported on the flex PCB backer 37. As the coverassembly 11 is secured in place by the clip element 154 gripping therecessed portion 155 of the cartridge unit support member 114, thecontacts 128 remain in aligned contact with the dimpled contacts 53,ensuring that power and data can be transmitted between the SoPECdevices 126 and the integrated circuits 50 of the printhead assembly 22.Due to the fact that the posts 156 act against the upright portion ofthe spring element 135, with the corresponding horizontal portion of thespring element 135 being secured against the arms 129, there is a returnforce stored in the spring element 135 such that when the latch 152 ofthe cover assembly 11 is released the PCB 125 and the arms 129 willbegin to pivot away from contact with the dimpled contacts 53 of theflex PCB 52, breaking electrical contact therebetween and allowing readyremoval of the cartridge unit 10.

As shown in FIGS. 78A-78C, the cover assembly 11 includes a centrallylocated docking port 157 in the form of a hole formed through the coverassembly 11. The docking port 157 is shaped to enable a refill unit 200to pass therethrough to dock with the cartridge unit 10 thereby enablingrefilling of the cartridge unit 10 with ink, in a manner which will bedescribed below. The docking port 157 has a rim portion 158 upon which aportion of the base of the refill unit 200 is received. Formed withinthe rim portion 158 of the docking port 157 is an engagement means 159which engages with the refill unit 200 to retain the refill unitsecurely in position to facilitate refilling of the cartridge unit 12. AQA chip reader 160 is also formed in the rim 158 of the docking port 157to mate with a corresponding QA chip provided in the refill unit 200 toensure integrity of the refill unit. The manner in which the engagementmeans 159 and the QA chip reader 160 functions will be described in moredetail later in the description.

Projecting into the docking port 157 via a hole 161 formed in the wallof the rim portion 158, as shown in FIG. 78C, is a push rod 162. Asshown more clearly in FIG. 82, the push rod 162 is in the form of anelongate bar member having an end 163 of reduced cross section whichextends through the hole 161 in the wall of the rim portion 158; and anend having a foot portion 164, a part of which extends perpendicular tothe length of the push rod 162. The body of the push rod 162, proximalthe foot portion 164, has a slot 165 formed therein which enables thepush rod 162 to be secured to the underside of the cover assembly 11 byway of a screw or the like upon which a push clip 166 is secured. Thepush clip 166 allows the push rod 162 to move longitudinally withrespect to the push clip 166 but prevents any sideways or downwardmovement of the push rod 162. A retainer 167 is also provided in theunderside of the cover assembly 11 proximal the docking port 157 toretain the push rod in position and to prevent any non-longitudinalmovement of the push rod 162. In this configuration, the pushrod 162 isfree to move in a longitudinal direction with respect to its length,such that the end 163 of reduced cross section can enter and bewithdrawn from the docking port 157. A spring element 168 is provided inthe slot 165 formed in the push rod 162 and acts to bias the push rod162 into position, such that its natural position is to have its end 163extend into the docking port 157.

The foot portion 164 of the push rod 162 is shown in more detail in FIG.83. The part of the foot portion 164 which extends perpendicular to thelength of the push rod, has a groove 169 formed therein. The surface 170of the groove is angled towards the end 163 of the push rod, as shown.The foot portion 164 is positioned at the side edge of the coverassembly 11 and extends in a downward direction with respect to thecover assembly 11. In this position the actuator arm 112 of the refillsolenoid assembly 111 mounted on the cradle unit 12 is orientated suchthat it is aligned with the groove 169 of the foot portion 164. As theactuator arm 112 is raised by the solenoid assembly 111 in a verticaldirection, it travels along the surface 170 of the groove 169 therebycausing the push rod 162 to retract such that the end 163 of the pushrod 162 no longer extends into the docking port 157. Lowering of theactuator arm 112 by the solenoid assembly 111 results in the push rod162 returning to its naturally biased position under the action of thespring element 168, whereby the end 163 extends into the docking port157. The manner in which the end 163 of the push rod interacts with therefill assembly 200 will be discussed in more detail below, however itshould be appreciated that the position of the push rod is controlled bythe SoPEC device 126 with regard to the state of operation of theprinter unit.

Refill Unit

FIG. 47 illustrates one embodiment of an ink refill unit 200. The inkrefill unit 200 generally comprises a base assembly 202 which housesinternal ink refilling components and a lid assembly 204 which fits ontothe base assembly 202. The base and lid assemblies may be moulded from aplastics material and the base assembly may be moulded as a single pieceor in sections (as shown in FIG. 88).

As mentioned previously, the refill unit 200 contains ink and isintended to be used as a means for refilling the ink storagecompartments 24 within the cartridge unit 10. The refill unit 200 isconfigured to dock with the surface of the cartridge unit 10 in order totransfer the ink it contains into the ink storage compartments 24 of thecartridge unit 10. For this purpose, the cover assembly 11 of the cradleunit 12 has a docking port 157 formed therein through which the refillunit 200 is able to pass to dock with the upper surface of the printcartridge 10.

As discussed previously in relation to the lid assembly 21 of thecartridge unit 10, the upper surface 60 of the lid assembly 21 has aplurality of ink refill ports 61 formed therein, with each of theindividual ink refill ports 61 being in fluid communication with one ofthe ink storage compartments 24 to deliver ink to that compartment. Theposition of the individual ink refill ports 61 on the surface of thecartridge unit 10 is specific to the type or colour of ink stored by thecartridge unit, and the position and configuration of the ink refillports 61 is consistent between different cartridge units. In thisregard, each refill unit 200 is configured with a plurality of outlets206 located in a bottom section 202 a of the base assembly 202 fordocking with the cartridge unit. However in each instance, only one ofthe outlets is in fluid communication with the supply of ink fordistributing ink to an ink storage compartment of the cartridge unitthrough the corresponding ink refill port, the position of the outletbeing dependant upon the type or colour of ink to be supplied from therefill unit. As shown in FIG. 88, the refill unit 200 is arranged withone working outlet 208 for the distribution of the particular colouredink contained in the refill unit to the ink refill port 61 of thecorrespondingly coloured ink storage compartment 24 in the cartridgeunit 10. That is, if the refill unit 200 contains cyan ink, the workingoutlet 208 is positioned so as to correspond to the ink refill port 61of the cyan ink chamber of the cartridge unit 10 when the refill unit isdocked with the cartridge unit.

A clip arrangement 210 is provided on at least one side of the baseassembly 202 of the refill unit 200 for securing the refill unit to theprint engine during the refilling operation. This ensures reliable andefficient transfer of ink from the refill unit 200 to the cartridge unitas the refill unit 200 is substantially immovable from the print engineuntil the clip arrangement 210 is disengaged, thereby ensuring acomplete seal between the refill unit and the cartridge unit andpreventing the possibility of ink spillage or air ingress between theoutlet and the ink refill port.

In this regard, the clip arrangement 210 is formed as a resilientsection of the side wall of the base assembly 202 and is movable withrespect the remainder of the side wall so as to engage and disengagewith a corresponding engagement means 159 provided in the docking port157 of the cover assembly 11 of the cradle unit. The clip arrangementincludes clip portions 212 in the form of projections that project froma resilient arm 214, the arm 214 being depressible to move into and outof a recess 216 about a pivot region 218, the pivot region 218 being aweakened region in the surface of the base assembly 202. In this way,when the bottom section 202 a of the base assembly 202 is moved intodocking engagement with the surface of the cartridge unit by beingpassed through the docking port 157 of the cover assembly, theengagement means 159 of the cover assembly comes into contact with theclip portions 212. This contact causes the arm 214 to deflect into therecess 216 as the refill unit is pushed into docking position with thecartridge unit, until the clip portions pass the engagement means 159 ofthe cover assembly. At this point, the arm 214 is no longer in contactwith the engagement means 159 and hence returns to its original positionthereby engaging the clip portions 212 with the lip of the engagementmeans 159.

The clip and engagement means of the refill unit and the cover assembly,respectively, are configured so that in the docked (refilling) position,the outlets 206, and most importantly the working outlet 208, of therefill unit 200 is snugly positioned on the refill ports of thecartridge unit.

Once refilling has been completed, the refill unit 200 can be removedfrom docking engagement with the cartridge unit, by depressing theresilient arm 214 such that the clip portions 212 disengage with the lipof the engagement means. Suitable detail ridges 222 may be provided onthe resilient arm 214 to provide grip for a user's finger(s) tomanipulate the clip arrangement 210.

The clip arrangement 210 and corresponding engagement portion 110 may beprovided on only one side of the refill unit 200 and cover assembly, ormay be provided on both (opposite) sides.

Within the refill unit 200 the ink is stored in a syringe-type assembly224. The syringe-type assembly 224 is mounted within the base assembly202 of the refill unit 200 so as to be covered by the lid assembly 204.The syringe-type assembly 224 has the necessary capacity to store theamount of ink required for refilling of the ink storage compartments ofthe cartridge unit. The components of the syringe assembly 224 are mostclearly seen in FIG. 90.

A tank 226 is provided in the syringe assembly 224 for storing the inkwithin the refill unit 200. The tank 226 has at one end an ejection port228 through which the ink is ejected for distribution and is sealed atthe other end by a syringe seal 230. The syringe seal 230 is mounted ona plunger 232 which is received within the hollow internal space of thetank 226 to expel the stored ink from the ejection port 228. The plunger232 is arranged to be driven into the hollow internal space of the tank226 under action of a compression spring 234. The compression spring isprovided within the plunger 232 and projects from the plunger to contactwith the internal end wall of the base assembly 202 (i.e., opposite theinternal end wall adjacent the ejection port 228 of the tank 226). Inthis way, the compression spring 234 applies a constant force to theplunger 232 urging it plunge towards the interior of the tank 226 whenthe syringe assembly 224 is housed in the base assembly 202.

Control of the plunging operation, and hence control of the delivery ofthe ink from the refill unit, is provided by ratchet arrangement of thesyringe assembly 224. The ratchet arrangement comprises an actuator rod236 which mounts at its upper end and an intermediate position towardsits lower end to mounting slots 238 provided on the tank 226. The rod236 has a pawl 240 projecting from one side thereof between thepositions mounted through the slots 238. The pawl 240 is engageable witha series of grooves providing a ratchet 242 on a side surface of theplunger 232.

The rod 236 is rotatable about its long axis so as to engage anddisengage the pawl 240 with the ratchet 242. An actuator spring 244 isprovided at the upper end of the rod 236 which acts against the sidesurface of the plunger 232 so as to bias the pawl 240 into the ratchet242. The engagement of the pawl 240 and the ratchet 242 providessufficient resistance against the plunging of the plunger 232 into theinterior of the tank 226 under action of the compression spring 234.

Thus, upon initial use of the refill unit 200, the pawl 240 is engagedwith the first groove of the ratchet 242, thereby preventing the plungerfrom substantially entering the interior of the tank 226 and in turnproviding maximum ink storage capacity within the tank 226. In order tocommence refilling of the cartridge unit, ink must be ejected from thetank 226 through the ejection port 228. This is achieved throughrotation of the rod 236 which disengages the pawl from the first groove.The plunger 232 then enters into the interior of the tank 226 underaction of the compression spring, causing ink to be ejected out theejection port 228. The pawl 240, following disengagement with the firstgroove, engages with the next groove of the ratchet 242 through thereturn action of the actuator spring 244 against the initial rotationthe rod 236. This causes movement of the plunger 232 within the interiorof the tank 226 to stop, thereby stopping delivery of ink from theejection port 228. More ink can be ejected from the tank 226 by repeatedrotation of the rod 236 and engagement/disengagement of the pawl 240with the ratchet 242, thereby providing incremental delivery of ink incontrolled amounts. This continues until the pawl engages with the finalgroove of the ratchet, at which point the ink within the tank 226 hasbeen depleted.

The rotation of the rod 236 to disengage the pawl 240 is caused byaction of an actuator shaft 246 on an arm 248 which projects from therod. The actuator shaft 246 is housed within the base assembly 202, asshown in FIG. 93, so as to be slidable along its long axis. One end ofthe actuator shaft 246 is slidable to contact the arm 248 of the rod 236when the syringe assembly 224 is mounted into the base assembly 202 andthe other end of the actuator shaft is slidable to be exposed to theoutside of the base assembly through a hole 202 b formed in one of itsend walls.

In order to performing the refilling operation, the exposed end of theactuator shaft 246 comes into contact with the end of the push rodprovided on the underside of the cover assembly, which projects into thedocking port of the cover assembly. The manner in which the push rodoperates has been discussed in detail above; however, when the refillunit 200 is in its refill position, the solenoid assembly can cause thepush rod to extend and push the actuator shaft 246 into contact with thearm 248 of the rod 236 so as to disengage the pawl 240 with the ratchet242, following which the push rod returns to its retracted position.Then, once the pawl 240 re-engages through action of the actuator spring244, the arm 248 of the rod 236 pushes the actuator shaft 246 back so asto be exposed again for subsequent contact by the push rod.

More ink is refilled from the refill unit 200 through repeated actuationof the push rod by the solenoid assembly, delivering controlled amountsof refill ink each time. As such, the refill cartridge is provided withthe ability to perform multiple refilling operations.

The status of the amount of the ink stored within the refill unit 200 ismonitored by a quality assurance (QA) control chip 250 provided in thebase assembly 202. Initially, the QA chip 250 may store information in amemory thereof such as the ink capacity of the tank 226 (e.g., about 50ml), the amount of ink which will be ejected from the tank with eachpawl/ratchet 240/242 shift (e.g., about 6 ml), the colour of the inkstored within the tank and the position of the working outlet 208.

In this regard, a sensor or other means is provided connected to the QAchip 250 which senses either the position of the pawl/ratchet or thenumber of times the rod 236 has been rotated by the actuator shaft 246or some other mechanism which informs the QA chip 250 of the remainingcapacity/number of refills of the refill unit. In this regard, thememory of the QA chip 250 is provided as a rewritable memory.

The QA chip 250 is provided in an exposed position on the end surface ofthe base assembly 202, such as in the vicinity of the hole 202 b for theactuator shaft 246 (see FIG. 88), so as to align and connect with thecorresponding QA chip reader provided within the rim of the docking portof the cover assembly.

The QA chip reader is connected to a QA chip and/or controller of theprint engine. In this way, the QA chip 250 is able to communicate theabove-described information to the print engine. For example, thecontroller of the print engine is able to check whether the ink storagecompartment of the cartridge unit containing the ink colour/type whichmatches the refill unit 200 requires refilling by the amount of at leastone pawl/ratchet shift. In response to such determinations, thecontroller controls the solenoid assembly so as to operate the push rodthe appropriate number of times to refill the corresponding ink chamber.

This communication between the refill unit 200 and the print engineensures that the correct type/colour of ink and the correct amount ofink is refilled into the correct ink storage compartment. Other checkscan be performed also, such as correct positioning of the working outlet208 on the appropriate refill port of the cartridge unit.

In order to deliver the refill ink into the refill ports, the workingoutlet 208 of the refill unit comprises a syringe needle 252 which isconnected to the ejection port 228 of the tank 226 through a fluidchannel 254 provided on the inner side and bottom surfaces of the baseassembly 202. Sealing between the ejection port 228 and the fluidchannel 254 is provided by an O-ring 256. The syringe needle 252 isarranged to penetrate the valve fittings provided within thecorresponding ink refill ports so as to allow the flow of ink into theink storage compartments.

As previously mentioned, the valve fittings may be provided as anelastomeric seal which seals the ink storage compartments from thesurroundings, thus preventing dust and the like entering the chambersand providing an elastically walled channel through which the syringeneedle 252 can pass.

Sealing between the working outlet 208 and the valve fittings isprovided by a seal ring 258 which surrounds the syringe needle 252. Inthe refill unit's isolated state, the syringe needle 252 is protected bythe seal ring 258 within the working outlet 208 (see FIG. 88). Whereas,in the refill position, the syringe needle 252 is exposed to the valvefitting by action of valve's upper surface on the seal ring 258 to pushthe seal ring into the working outlet 208. The seal ring 258 is able to‘ride’ up the syringe needle 252 and upon release from the refillposition, the seal ring is returned to its protection position viaaction of a seal spring 260 situated between the seal ring and the innersurface of the fluid channel 254 above the syringe needle. The sealspring 260 is held to the seal ring 258 with a support washer 262.

An exemplary refilling operation is illustrated in FIG. 94A to 94C.

In FIG. 94A, the refill unit 200 is in its refilling position with thesyringe needle 252 penetrating the valve fittings of an ink storagecompartment of the cartridge unit. At the stage shown, ink 264 storedwithin the tank 226 has been primed into the fluid channel 254 and thesyringe needle 252. Alternatively, the fluid channel 254 may compriseair or other gas at this stage, e.g., before the first refillingoperation for the refill unit has been performed. The ink is held withinthis fluid path without escaping through the syringe needle due tovacuum pressure created in the fluid path.

Alternatively, a cap may be provided to be either manually orautomatically fitted within the working outlet so as to cap the end ofthe syringe needle. Such a cap additionally provides a means of ensuringthat the stored ink does not dry out before the first application andbetween multiple refill applications.

In FIG. 94A, the actuator arm of the solenoid assembly of the cradleunit is operated to extend the push bar into contact with the actuatorshaft 246, moving the actuator shaft 246 into contact against the arm248 of the rod 236. Immediately after this, the push bar returns to itsretracted position of FIG. 94A. The pawl 240 is then disengaged from theratchet groove 242, thus causing the compression spring 234 to depressthe plunger 232 into the tank 224 in the direction of arrow A. As aresult, ink 264 is ejected from the ejection port 228 and thus throughthe syringe needle 252 into the ink storage compartment in the directionof arrow B.

In FIG. 94C, the plunger 232 has moved sufficiently for the pawl 240 toengage with the next ratchet groove 242. At this point, the plunger 232is stopped and as such the ejection of the ink 264 from the syringeneedle 252 ceases.

The above process may be repeated until the ink chamber 122 is deemedrefilled by the controller of the printer unit or until the refill unit200 is depleted of ink. The status of the amount of ink in the refillunit 200 can be relayed to a user through the operation of an indicatorlight 266, such as an LED, provided on the lid assembly 204. Theindicator light 266 is connected to the QA chip 250 when the lidassembly 204 is fitted to the base assembly 202, and may be operated toilluminate during the refilling operation and cease illumination whenthis operation is finished and when the refill unit 200 is depleted.Alternatively, the indicator light 266 may be capable of multi-colouredillumination, such that different light colours are used to indicate theparticular status of the refill unit 200, e.g., a green light duringrefilling; a red light when the refill unit is depleted.

Power for the indicator light 266 and the QA chip 250 may be providedvia the connection with the QA chip reader. Alternatively, a battery maybe provided within the refill unit 200 having a power capacitysufficient for operating the unit until the ink is depleted.

An alternative embodiment of a syringe assembly 268 housed within therefill cartridge 200 is illustrated in FIGS. 95 to 99. Like the syringeassembly 224 of the previous embodiment, the syringe assembly 268 ismounted within the base assembly 202 of the refill unit 200 so as to becovered by the lid assembly 204 and has the necessary capacity to storeand distribute the amount of ink required for refilling to the printcartridge 102 through the working outlet 208.

Like the syringe assembly of the previous embodiment, the syringeassembly 268 is provided with the tank 226 for storing the ink withinthe refill unit 200. The tank 226 has at one end the ejection port 228through which the ink is ejected for distribution and is sealed at theother end by the syringe seal 230. The syringe seal 230 is mounted onthe plunger 232 which plunges into the hollow internal space of the tank226 to drive the stored ink out of the ejection port 228.

The plunger 232 is plunged into the tank 226 through action of acompression spring 270 which is attached at one and about thecircumference of the body 232 a of the plunger 232. The other end of thespring 270 acts against a ring 232 b fixed between posts 272 whichproject from the lower internal surface of the base assembly 202. Inthis arrangement, due to the nature compression spring 270, it acts toconstantly bias the plunger 232 towards the interior of the tank 226when the syringe assembly 268 is housed in the base assembly 202, as didthe earlier described embodiment.

In this instance, control of the plunging operation is provided by apawl and ratchet arrangement of the syringe assembly 268. The pawl andratchet arrangement comprises an actuator rod 274 which is mounted viapins 274A, between its upper and lower ends, to mounting slots 276 whichproject from the lower internal surface of the base assembly 202. Inthis way, the rod 274 is able to swing or pivot about the mounted pins274A.

The rod 274 has a pawl 278 at its upper end which is engageable with aseries of teeth of a ratchet 280 provided in a circular arrangement atone end of a feed member 282 (best illustrated in FIG. 98). The swingingof the rod 274 enables the pawl to engage and disengage with theratchet. An actuator spring 284 is provided between a boss 274B, whichprojects from the lower end of the rod 274, and an internal surface ofthe base assembly to bias the pawl into the ratchet.

The feed member 282 is in the form of a cylindrical wheel and is mountedat either end to the posts 272 via pins 272 a which project into axialholes (not shown) in the ends of the feed member 282. In this way, thefeed member 282 is able to rotate about its longitudinal axis. The feedmember 282 further comprises a grooved thread 286 about itscircumference at the end opposite the ratchet 280. The grooved thread286 is used to train a rope 288 about the feed member 282. One end ofthe rope is attached to the end of the grooved thread and the other endof the rope attached to, or through, the plunger body 232 a.

Prior to shipment of the refill unit 200, the combination of the rope288 and grooved thread 286 and the ratchet and pawl arrangement is usedto initially retract the plunger 232 from the tank 226 so as to providea space in which to store the ink. In this regard, the feed member 282is provided with a gear 290 which is able to mesh with an external motorgear or the like. Action of the motor gear rotates the feed member (in aclockwise direction in the arrangement shown in FIG. 97) whilst the pawlis not engaged with the ratchet which causes the rope to be wound aboutthe grooved thread, thus retracting the plunger from the tank 226against the action of the spring 270.

Sufficient rotational force is required to compress the spring 270 andsufficient strength is required in the rope to hold the plunger in placewhilst the spring is compressed. Once the plunger has been pulled out ofthe tank in which position the spring is substantially fully compressed,the pawl is engaged with the nearest tooth of the ratchet. Thisengagement provides sufficient resistance against the plunging of theplunger 232 into the interior of the tank 226 through action of thecompression spring 270. The tank 226 can then be primed with ink forshipment.

Thus, upon first use of the refill unit 200, the pawl 278 is engagedwith the tooth of the ratchet 280 which provides maximum ink storagecapacity within the tank 226. As ink is required to be ejected from thetank 226 through the ejection port 228 during a refilling operation, therod 274 is swung to disengage the pawl with the tooth of the ratchet.This causes the plunger 232 to advance into the tank 226 a set distancethereby ejecting a measured portion of the stored ink through theejection port 228. Ejection stops when the pawl 278 engages with thenext tooth of the ratchet 280, which occurs through action of theactuator spring 284 swinging the rod 274 into engagement with theratchet.

Additional measured portions of ink can be ejected from the tank 226 byrepeated swinging of the rod 274 thereby causingengagement/disengagement of the pawl with the ratchet. This continuesuntil the rope 288 and the compression spring 270 are fully extended atwhich point the ink within the tank 226 is depleted and the refill unit200 is spent.

Similar to the previous embodiment, the swinging of the rod 274 todisengage the pawl 278 can be controlled by way of a slider elementprovided on the underside of the cover assembly 11 contacting the lowersurface of the rod opposite the boss 274B. As discussed in relation tothe previous embodiment, the lid assembly can be configured such that anend of the slider element projects into the docking port 157 and througha hole 202 c formed in one of the side walls of the base assembly 202when the refill unit is docked with the cartridge unit 10. The other endof the slider element may be connected to a refill solenoid assemblywhich is attached to the cradle unit as described previously.

In this way, when the refill unit 200 is docked with the cartridge unit10 and is in a refill position, the slider element can be operated topush the rod 274 so as to disengage the pawl 278 with the ratchet 280.Then, once the pawl re-engages through action of the actuator spring284, the lower end of the rod 274 is repositioned for subsequent contactby the slider element.

More ink is refilled from the refill unit 200 through repeated slidingof the slider element. Equally, multiple refill operations using the onerefill unit 200 can be performed if any one refill operation does notdeplete the ink contained therein. As such, the refill unit is providedwith the ability to perform multiple refilling operations.

The clip arrangement 210 and the arrangement of the syringe needle 252in the working outlet 208 and the QA chip 250 is the same for the refillcartridge incorporating this alternative syringe assembly 268 as that ofthe previous embodiment.

With this alternative embodiment of the syringe assembly 268 a largervolume of ink can be stored within the tank 226 of the refill unit 200(e.g., about 50 ml) whilst retaining a similarly size to that in theprevious embodiment. This is because, the space occupied by the pawl andratchet arrangement is minimised whilst retaining a sufficient number ofsteps for controlled ejection of ink for refilling.

FIGS. 100 to 106 illustrate yet another embodiment of an ink refill unit400 suitable for use with the print engine of the present invention.

The ink refill unit 400 generally comprises a body assembly 402, forhousing the various internal components necessary for storing anddelivering the refill ink, and an end cap assembly 404 which fits ontoand caps an end of the body assembly 402. The body and cap assembliesmay be moulded from a plastics material.

As in the embodiments described above, the refill unit 400 contains inkand is intended to be used as a means for refilling ink storagecompartments 24 provided within the cartridge unit 10. In this regard,the refill unit 400 is configured to dock with the uppermost surface 60of the cartridge unit 10 to transfer the ink contained therein into oneor more of the ink storage compartments 24 of the cartridge unit 10 inthe manner as discussed previously.

In this regard, the refill unit 400 is also arranged with at least oneworking outlet 408 (see FIG. 102) for distributing a particular colouror type of ink contained in the refill unit to the corresponding inkrefill port 61 associated with the desired ink storage compartment 24 ofthe cartridge unit 10. That is, if the refill unit 400 contains cyanink, the working outlet 408 is positioned so as to correspond to the inkrefill port 61 associated with the cyan ink storage compartment of thecartridge unit 10 when the refill unit is in its refilling position.

Although not shown in the drawings, a clip arrangement similar to thatof the earlier described embodiment may be provided on the body assembly402 and within the rim portion 158 of the docking port 157, to ensurereliable and efficient transfer of ink from the refill unit 400 to thecartridge unit 10.

The body assembly 402 of the ink refill unit 400 has capacity to store asufficient amount of ink required to refill the ink storage compartments24 of the cartridge unit 10. The internal components of the bodyassembly 402 are most clearly seen in FIGS. 103 to 106.

A compressible bellows tank 410 is provided in the body assembly 402 forstoring the ink. In this regard, the bellows tank is sealed at one endand is provided with an ejection port 412 at the other end (being theend adjacent the end wall of the body assembly) through which the ink isejected for distribution. The sealed end of the bellows tank 410 abuts aplunger 414 which is arranged to compress the bellows tank against theend wall of the body assembly to expel the stored ink out of theejection port 412.

The plunger 414 compresses the bellows tank 410 through action of a gearand thread arrangement. The gear and thread arrangement comprises ahelical geared thread 416 provided about the circumference of thesubstantially circular plunger 414 which mates with an elongate drivegear 418 which is mounted within the body assembly 402 and extends alongthe length thereof, and an internal lead screw thread 420 provided inthe substantially cylindrical internal wall of the body assembly (seeFIG. 106). The lead screw thread 420 is provided with a gap along thelength of the body assembly 402 in which the drive gear 418 sits and isable to come into contact with the gear teeth in the gear thread 416 ofthe plunger 414. An elongate protruded region 422 of the body assembly402 is provided to accommodate the drive gear 418 in this position.

In this gear and thread arrangement, the plunger 414 is able to rotateso as to move along the lead screw thread 420. This movement providesthe plunging operation of the plunger against the bellows tank. Therotation of the plunger is provided by rotation of the drive gear 418being imparted to the geared thread 416 of the plunger. The drive gear418 is held within the protruded region 422 by a pin 418 a provided onone end of the drive gear which slides into a depression or hole withinthe internal end wall of the body assembly 402 and a pin 404 a providedin a corresponding position on the internal surface of the end capassembly 404 which slides into a corresponding depression 418 b providedon the other end of the drive gear. Other arrangements are possiblehowever, so long as the drive gear is free to rotate about its longaxis.

The rotation of the drive gear 418 is driven by a motor gear 124 whichmeshes with the teeth of the drive gear. The motor gear 124 is driven bya motor which may be mounted to the underside of the cover assembly 11of the cradle unit 12. In this arrangement, similar to those describedin the above alternative embodiments, the motor gear 124 is arranged toproject from the surface of the cover assembly to engage with the drivegear 418 through a slot 422 a in the protruded region 422. Those ofordinary skill in the art will understand that the motorisation of thegear and thread arrangement may also be provided within the refill unit400 itself instead of in the cover assembly 11.

Control of the plunging operation is provided by the controlling theoperation of the motor responsible for rotating the motor gear 124, anda suitable gearing ratio may be provided for reasonably fine control ofthe plunger movement. As will be appreciated, the plunging operationprovides controlled release of the ink from the bellows tank 410 throughits ejection port 412.

Upon first use of the refill unit 400, plunger 414 is fully retracted soas to provide full extension of the bellows tank and hence maximum inkstorage capacity in the refill unit 400. Of course, suitably sizedbellows tanks can be provided within the same sized refill units 400 forprovided different storage amounts, e.g., 30 ml as opposed to 50 ml,depending on application, the colour of the ink, etc. Then, as ink isrequired to be ejected from the bellows tank 410 during a refillingoperation, the motor may be controlled to rotate the motor gear 124 andthe drive gear 418 thereby causing the plunger 414 to compress thebellows tank to eject some of the stored ink through the ejection port412. The amount of ink ejected per rotation of the motor gear 124 can bereadily ascertained to provide metered release of ink into the cartridgeunit 10 as necessary.

The plunging is continued until the required amount of ink has beenejected into the ink storage compartments of the cartridge unit 10. Forexample, in a single-use refill operation, the entire contents of therefill unit 400 would be ejected, however in a multiple-use refilloperation, only part of the refill unit's capacity of ink may berequired at one time. In such a multiple-use regime, more ink can beejected from the bellows tank by repeated plunging operations until theink within the bellows tank has been depleted. The ink may be dispensedin a series of preselected amounts, e.g., by a series of preselectednumbers of turns of the plunger 414, until the necessary amount of inkhas been dispensed, or the plunger 414 may be simply turned until it isdetermined that the ink chamber has been replenished.

In order to ensure that the ink does not leak from the ejection port 412after a refilling operation has been performed and ink remains in thebellows tank for subsequent refills, suitable fluid pressure is retainedwithin the bellows tank 410 at all times. This is achieved by backing-upthe plunger 414 by a suitable amount once the refilling operation iscomplete. This is done by rotating the plunger in the opposite directionso as to allow slight re-expansion of the bellows tank 410. In thisregard, the sealed end of the bellows tank is preferably attached to theplunger and the motor provided in the cover assembly 11 is preferably abi-directional motor.

Like the previous embodiments, the status of the amount of the inkstored within the refill unit 400 is monitored by a QA control chip 424provided in the body assembly 402. The QA chip 424 is provided in anexposed position on the surface of the end cap assembly 404, oralternatively on the end surface of the body assembly 402, so as toalign and connect with a QA chip reader 160 provided in the docking port157 of the cover assembly 11. The QA chip reader is in turn connected tothe SoPEC devices 126 of the cradle unit 12 to enable control of theoverall refill operation. In the present embodiment, the QA chip 424 isused to provide information on the amount of ink (and colour, etc)stored in the refill unit 400 at any instant to the SoPEC devices 126,so that the SoPEC devices can control the motor to rotate the motor gear124 the appropriate number of times to refill the corresponding inkstorage compartment 24.

In this regard, a sensor or other means may be connected to the QA chip424 to sense either the position of the plunger 414 or the number oftimes the plunger 414 has been rotated by the drive gear 418 whichinforms the QA chip 424 of the remaining capacity/number of refills ofthe refill unit 400.

As with the first embodiment, the working outlet 408 of the refill unit400 comprises a syringe needle 426 which is connected to the ejectionport 412 of the bellows tank 410 through a fluid channel 428 provided onthe outer sides of the body assembly 402 (see FIG. 102). Sealing betweenthe ejection port 412 and the fluid channel 428 is provided by an O-ring430. The syringe needle 426 is arranged to penetrate the valve fittings62 provided within the ink refill ports 61 of the cartridge unit 10 soas to allow the flow of ink into the ink storage compartments 24. Thearrangement and operation of the syringe needle 426 is otherwise thesame as in the first embodiment.

An indicator light (not shown) may be provided on the body assembly 402of the refill unit 400 connected to the QA chip 424 so as to indicatethe status of the amount of ink in the refill unit to a user. Power forthe indicator light and the QA chip may be provided via the connectionto the contact 130 of the print cradle 100. Alternatively, a battery maybe provided within the refill unit 400 having a power capacitysufficient for operating the unit until the ink is depleted.

While the present invention has been illustrated and described withreference to exemplary embodiments thereof, various modifications willbe apparent to and might readily be made by those skilled in the artwithout departing from the scope and spirit of the present invention.Accordingly, it is not intended that the scope of the claims appendedhereto be limited to the description as set forth herein, but, rather,that the claims be broadly construed.

1. A printing fluid refill cartridge for a printing unit having refillports each corresponding to a different colour of printing fluid and apush rod for powered actuation between an extended position and aretracted position, the printing fluid refill cartridge comprising: anoutlet arranged to be engageable with one of the refill ports; a firstengagement member arranged in the vicinity of the outlet for releasableengagement with a second engagement member arranged in the vicinity ofthe refill port; a syringe assembly containing the printing fluid, thesyringe assembly having a plunger biased to discharge the printing fluidfrom the syringe assembly; a ratchet connected to the plunger; and, apawl for releasably engaging the ratchet to stop movement of the plungerthereby preventing discharge of the printing fluid; wherein, the firstengagement member is configured to secure the refill cartridge to theprinting unit such that the outlet engages the refill port correspondingto the printing fluid colour in the syringe assembly and positions thepawl for engagement with the push rod in the extended position todisengage the pawl from the ratchet such that a controlled amount of theprinting fluid is dispensed into the printing unit.
 2. A refillcartridge according to claim 1, wherein the first engagement member isconfigured so that a syringe needle arranged in the outlet fordistributing the printing fluid penetrates and is held within a valveseal of the refill port when engaged with the second engagement member.3. A refill cartridge according to claim 1, wherein the first engagementmember is a slot and the second engagement member is a movableprotrusion engageable with the slot.
 4. A refill cartridge according toclaim 1, wherein the second engagement member is a slot and the firstengagement member is a movable protrusion engageable with the slot.
 5. Arefill cartridge according to claim 1, further comprising a side wallhaving a movable region whereby movement of the movable region providesengagement and disengagement of the first and second engagement members.6. A refill cartridge according to claim 5, wherein the movable regionincorporates a depressible region of the at least one side wall.
 7. Arefill cartridge according to claim 1, wherein the printing unit is aprinter cartridge mountable to a printer, and the refill portcommunicates with a printing fluid storage chamber of the printercartridge which distributes printing fluid to a printhead.
 8. A refillcartridge according to claim 7, wherein the printhead incorporates apagewidth printhead arranged to print printing fluid across the width ofsheets of print media.
 9. A refill cartridge according to claim 7,wherein the printhead incorporates a pagewidth printhead arranged as atwo-dimensional array of at least 50,000 printing nozzles for printingacross the width of sheets of print media.
 10. A refill cartridgeaccording to claim 7, wherein the printhead incorporates an array ofprinting fluid ejecting nozzles configured as a pagewidth printheadarranged to print on sheets of print media by ejecting at least 1200drops of printing fluid per inch across the width of the sheets.
 11. Arefill cartridge according to claim 7, wherein the printheadincorporates an array of printing fluid ejecting nozzles configured as apagewidth printhead arranged to print on sheets of print media byejecting drops of printing fluid across the width of the sheets with adrop ejection energy of less than about 250 nanojoules per drop.
 12. Arefill cartridge according to claim 7, wherein the printheadincorporates a pagewidth printhead arranged to print printing fluidacross the width of sheets of print media at a rate of at least 60sheets per minute.
 13. A refill cartridge according to claim 7, whereinthe printhead incorporates an array of printing fluid ejecting nozzlesconfigured as a pagewidth printhead arranged to print on sheets of printmedia by ejecting drops of printing fluid across the width of the sheetsat a rate of at least 500 million drops per second.